NEW HOLLAND D255 CRAWLER DOZER Service Repair Manual

D255
Print No. 84568074A
Crawler Dozer
SERVICE MANUAL

Study SAFETY RULES in the front of this manual thoroughly for the protection of machine and safety of personnel.
THIS ALERT SYMBOL SIGNALS IMPORTANT MESSAGES INVOLVING YOUR SAFETY.
Readandheedcarefullythesafetyinstructionslistedandfollowtheprecautionsrecommendedtoavoidpotential
risks and to safeguard your health and your safety.
You will find this symbol in the text of this Manual referred to the following key words:
WARNING - Cautions directed to avoid improper repair interventions involving potential consequences for the
operator’s safety.
DANGER - These warnings qualify specifically potential dangers for the safety of the operator or other persons
directly or indirectly involved.
IMPORTANT NOTICE
All maintenance and repair interventions explained in this Manual must be performed exclusively by the Service
Organization of the Manufacturer, observing strictly the instructions explained using, whenever necessary, the
recommended specific tools.
Whoever performs the operations reported without following exactly the precautions is responsible on his own, for
the damages that may result.
Neither the Factory nor any Organizations in its Distribution Network, including but not limited to national, regional
or local distributors, are responsible for any liability arising from any damage resulting from defects caused by parts
and/or components not approved by the Factory for use in maintaining and/or repairing products manufactured or
merchandized by the Factory.
In any case, no warranty of any kind is made or shall be imposed with respect to products manufactured or
merchandized by the Factory, when failures are caused by the use of parts and/or components not approved by the
Factory.
D255
CRAWLER DOZER
Service Manual
Print N° 84568074A English

Study SAFETY RULES in the front of this manual thoroughly for the protection of machine and safety of personnel.
AVOID ACCIDENTS
Most accidents and injuries occurring in industry, on
the farm, at home or on the road, are caused by the
failure of some individual to follow simple and funda-
mental safety rules or precautions. For this reason,
MOST ACCIDENTS CAN BE PREVENTED by recog-
nizing the real cause and taking the necessary precau-
tions, before the accident occurs.
Regardless of the care used in design and construction
of any type of equipment, there may be conditions that
cannot be completely safeguarded against without
interfering with reasonable accessibility and efficient
operation.
A careful operator is the best insurance against acci-
dents. The complete observance of one simple rule
would prevent many thousands serious injuries each
year.
This rule is: Never attempt to clean, lubricate or adjust
a machine while it is in motion.
WARNING
On machines having hydraulically, mechanically
and/or cable controlled equipment (such as
showels, loaders, dozers, scrapers etc.) be certain
the equipment is lowered to the ground before
servicing, adjusting and/or repairing.
If it is necessary to have the equipment partially or
fully raised to gain access to certain items, be sure
the equipment is suitably supported by means
other than the hydraulic lift cylinders, cable and/or
mechanical device used for controlling the equip-
ment.

SUMMARY
GENERALITIES SECTION 0
ENGINE SECTION 1
TRANSMISSION-TORQUE CONVERTER SECTION 2
STEERING CLUTCHES - BRAKES SECTION 3
FINAL DRIVES SECTION 4
UNDERCARRIAGE SECTION 5
DOZER EQUIPMENT
HYDRAULIC SYSTEM SECTION 6
ELECTRICAL SYSTEM SECTION7
AIR CONDITIONING UNIT SECTION 8
SECTION 7
SECTION 1
SECTION 6
SECTION 3
SECTION 5 SECTION 2 SECTION 4
SECTION 8

TITLE PAGE
SAFETY RULES ................................................................................................... I - VIII
TECHNICAL DATA TABLES .................................................................................. 1 - 15
GENERAL INSTRUCTIONS ................................................................................ 16 - 20
DIAGNOSTIC CHECKS ............................................................................................... 21
MEASURE UNITS ....................................................................................................... 22
CLASSIFICATION OF STANDARD PARTS ................................................................ 22
TIGHTENING TORQUES ............................................................................................ 23
SECTION 0
GENERALITIES
TABLE OF CONTENTS

I
Study this Manual before starting, operating, maintaining, fuelling or servicing the machine.
Read and heed all safety rules before any intervention.
- Be sure all protective guards or panels are in place, and
all safety devices provided are in place and in good
operating conditions.
- Be sure exposed personnel in the area of operation are
clear of the machine before moving it or its attachments.
WALK COMPLETELY AROUND the machine before
mounting. Sound horn. Obey flag man, safety signals
and signs.
- Before starting machine, check, adjust and lock the
operator’s seat for maximum comfort and control of the
machine.
- Fasten your seat belt (when provided).
- Obey all flag signals and signs.
- Due to the presence on the machine of flammable fluids,
never check or fill fuel reservoirs or batteries near open
flames, smoking materials or sparks.
- REMEMBERTHATSTARTINGFLUIDISFLAMMABLE.
Follow recommendations printed on containers and in
the Operation and Maintenance Manual.
- DO NOT PUNCTURE OR BURN CONTAINERS.
- Containers must be stored in fresh, well ventilated
places, out of reach of unauthorised persons. Follow
strictly the instructions provided by the Manufacturer.
- Never use these preducts near open flames, smoking
materials or sparks.
OPERATION
- Do not run the engine of this machine in closed areas
withoutproperventilationtoremovedeadlyexhaustgases.
- Roll Over Protective Structures are required on loaders,
dozers, graders, excavators. NEVER OPERATE ma-
chines without ROPS.
- Make sure the Operator’s compartment is free of foreign
objects, especially if not firmly secured. Never use the
machine to transport objects, unless proper securing
points are provided.
- Check monitoring instruments at start-up and frequently
during operation if the brake pressure gauge sugnals a
pressure lower than the minimum operation value, stop
immediately the machine.
WARNING
SAFETY RULES
- Do not allow unauthorised personnel to operate service
or maintain this machine.
- Do not wear rings, wrist watches, jewellery, loose or
hanging apparels, such as ties, torn clothing, scarves,
unbuttoned or unzipped jackets that can catch on mov-
ing parts. Wear proper safety equipment as recom-
mended for the job. Examples: hard hat, heavy gloves,
ear protection, safety glasses or goggles, reflector vests,
respirator. Consult your employer for specific safety
equipment requirements.
- Keep operator’s compartment, stepping points, grab-
rails and handles clear of foreign objects, oil, grease,
mud or snow accumulation to minimize the danger of
slipping or stumbling.
Clean mud or grease from shoes before attempting to
mount or operate the machine.
- Do not jump on or off the machine. Keep two hands and
one foot, or two feet and one hand in contact with step
grab rails and handles at all times.
- Do not use controls or hoses as hand holds when
climbing on or off machine. Hoses and controls are
movable and do not provide a solid support. Controls
also may be inadvertently moved causing accidental
machine or equipment movement.
- Never attempt to operate the machine or its tools from
any position other than seated in the operator’s seat.
- Keep head, body, limbs, hands and feet inside opera-
tor’s compartment at all times to reduce exposure to
hazards outside the operator’s compartment.
- Be careful of slippery conditions on stepping points,
hand rails, and on the ground. Wear safety boots or
shoes that have a high slip resistant sole material.
- Do not leave the machine until it is completely stopped.
- Check the seat safety belt at least twice a year. If there
are signs of wear or fraying or other signs of weakness
that could lead to failure, replace it.
STARTING
- NEVER START OR OPERATE AN UNSAFE MACHINE.
Before operating a machine, always ensure that any
unsafe condition has been satisfactorily remedied.
- Check brakes, steering and attachment controls before
moving. Advise the proper maintenance authority of any
malfunctioning part or system.

SAFETY RULES
- Be sure chains and cables are anchored and the anchor
points are strong enough to handle the expected load.
Keep exposed personnel clear of anchor points and
cables or chains.
- DO NOT PULL UNLESS OPERATOR’s COMPART-
MENT OF MACHINES INVOLVED ARE PROPERLY
GUARDED AGAINST POTENTIAL CABLE OR CHAIN
BACKLASH.
- Be alert to soft ground conditions close to newly con-
structed walls. The fill material and weight of the machine
may cause the wall collapse under the machine.
- In darkness, check area of operation carefully before
moving in with machine. Use all lights provided. Do not
move into area of restricted visibility.
- If engine has a tendency to stall for any reason under
load or idle, report this for adjustment to proper mainte-
nance authority immediately.
Do not continue to operate machine, until condition has
been corrected.
- On machines supplied with suction radiator fans, be sure
to periodically check engine exhaust parts for leaks, as
exhaust fumes are dangerous to the operator.
- In case of enclosed cabs, always let open a discharge
to the outside, to ensure air circulation.
- Operators must know thoroughly the performances of
the machine they are operating.
When working on slopes or near sudden level drops of
the terrain, avoid areas where ground is loose or soft
since rolling-over or loss of control of machine could
result.
- Where noise exposure exceeds 90 dBA for 8 hours, wear
approved ear protection.
- When counterweights are provided, do not work ma-
chine if they have been removed.
- Overtaking manoeuvres must be performed only when
absolutely necessary and unavoidable.
Beware of possible uneven terrains, poor visibility con-
ditions, the presence of other machinery or persons out
of sight.
- Operate the machine at a speed adequate to the working
conditions in the site and slow enough to ensure com-
plete control at all times.
- Check monitoring instruments at start-up and frequently
during operations.
In case of abnormal condition warnings, stop immedi-
ately the machine.
- Never use the machine as a work platform or scaffolding,
nor other inappropriate operations (i.e pushing railway
cars, trucks or other machines).
- DO NOT CARRY RIDERS ON MACHINE
- Study and familiarize with escape routes alternate to
normal exit routes.
- Seat belts are required to be provided with Roll Over
ProtectionStructuresorcabs.Keepsafetybeltsfastened
around you during operation.
- For your personal protection, do not climb on or off
machine while machine in motion.
- Make sure that exposed persons in the area of operation
are clear of the machine, before starting the engine and
operating the equipment. Obey all indications provided
by flags and signals.
- NEVER COAST the machine down grades and slopes
with the transmission in neutral or neutralized, or power
shift type machines, or clutch disengaged on manually
shifted machines.
- Do not operate machinery in a condition of extreme
fatigue or illness. Be especially careful towards the end
of working shift.
- Do not operate machine with brakes out of adjustment.
- Operate the machine at speeds slow enough to ensure
complete control at all times.
- Travel slowly over rough terrain, on slopes or near drop-
offs, in congested areas or on ice or slippery surfaces.
- When backing, always look to where the machine is to
be moved.
Be alert to the position of exposed personnel. DO NOT
OPERATE if exposed personnel enter the immediate
work area.
STOP THE MACHINE.
- Maintain a safe distance from other machines. Provide
sufficient clearance for ground and visibility conditions.
Yield right-of-way to loaded machines.
- Maintain clear vision of areas of travel or work. Keep cab
windows clean and repaired.
- When machines are operating in tandem, the pusher
(rear) must be equipped with the appropriate deflectors
to protect the unit in front from the air stream coming from
the radiator.
- When pulling or towing through a cable or chain, do not
start suddenly at full throttle; take-up slack carefully.
Inspect carefully for flaws or troubles before using.
- Avoid kinking chains or cables. Do not pull through a
kinked chain or cable to the high stresses and possibility
of failure of the kinked area.
Always wear heavy gloves when handling chains or
cables.
II

SAFETY RULES
- Be alert of people in the operating area of the machine.
When operating a machine, know what clearances will
be encountered, overhead doors, cables, pipes, bear-
ing load limitations of ground, bridges, floors or ramps.
- When roading, find-out what conditions are likely to be
encountered, clearances, traffic congestion, type of road
surfacing, etc.
Beware of fog, smoke or dust elements that obscure
visibility.
- When crossing gullies or ditches, move at an angle with
reduced speed after ensuring ground conditions will
permit a safe traverse.
- Explore the working area to identify potential risks such
as: slopes, overhangs, pits, demolition rubble, fires,
ravines, ditches, soft terrain, heavy traffic, crowded park-
ing areas, closed ambients. In such conditions, proceed
with extreme care.
- Whenever possible, avoid going over obstacles such as
rough terrain, rocks, logs highly irregular ground, steps,
ditches, railroad tracks. When obstructions must be
crossed, do so with extreme care at an angle, if possible.
Reduce speed, shift-down.
Ease up to the break over point, pass the balance point
slowly on the obstruction and ease down on the other
side.
- In steep down-hill operation, do not allow engine to over-
speed. Select proper gear before starting down grade.
- Avoid side hill travel, whenever possible. Drive up and
down the slope. Should the machine slipping sideways,
turn it immediately downhill.
- The grade of slope you should attempt will be limited by
factors such as condition of the ground, load being
handled, type of machine, speed of machine and visibil-
ity.
- There is no substitute for good judgement when working
on slopes.
- Avoid operating equipment too close to an overhang or
high wall, either above or below the machine. Be on the
look-out for caving edges, falling objects and slides.
Beware of concealment by brush and undergrowth of
these danger.
- When pushing-over trees, the machine must be
equipped with proper overhead guarding. Never allow
a machine to climb up on the root structure particularly
while the tree is being felled.
Use extreme care when pushing over any tree with dead
branches.
- Avoid brush piles, logs or rocks. NEVER DRIVE OVER
THEM or other surface irregularities that brake traction
with the ground, especially when on slopes or near drop-
offs.
- Be alert to avoid changes in traction conditions that could
cause loss of control. DO NOT DRIVE on ice or frozen
ground conditions when working the machine on steep
slopes or near drop-offs.
- Working in virgin and rough terrains is characterized by
the presence of all the perils and risks listed above. In
these conditions, it is emphasised the danger repre-
sented by large tree limbs (possibly falling on the ma-
chine), large roots (acting as a leverage under the
machine when up-rooted causing the roll-over of the
unit) etc..
STOPPING
- When the machine is stopped for whatever reason,
follow the instructions of chapters “Stopping the ma-
chine”and“Stoppingtheengine”oftheOperationand
Maintenance Instruction Manual.
- Always remember to position the transmission drive
control in neutral and engage the control lock to secure
the machine.
- Set parking brake.
- NEVER LEAVE THE MACHINE UNATTENTED with the
engine running.
- Always before leaving the operator’s seat and after
making sure all people are clear of the machine, slowly
lower the attachments or tools flat to the ground in a
positive ground support position.
- Return the controls in neutral position. Place the gear-
shift lever in neutral and shut-off the engine. Lock the
gearshift lever, switch-off and lock the starter switch.
- Park in a non- operating and no-traffic area or as in-
structed. Park on firm level ground if possible. Where not
possible, position machine at a right angle to the slope,
making sure there is no danger of uncontrolled sliding
movements. Set parking brake.
- If parking in traffic lanes cannot be avoided, provide
appropriate flags, barriers, flares and signals as re-
quired. Also provide advance warning signals in the
traffic lane of approaching traffic.
- Keep head, body, limbs, hands and feet away from
blade, arms, bucket or ripper when in raised position.
Always disconnect the master switch before any inter-
vention (i.e. cleaning, repairing, maintaining, refuelling
etc.). Do the same when parking for prolonged periods
of time to avoid accidental or unauthorized starting.
- Never lower attachments or tools other than seated in
operator’s seat. Sound horn. Make sure area near the
attachment is clear. Lower the attachment slowly. DO
NOT USE FLOAT POSITION of hydraulic system.
III

SAFETY RULES
- Securely block the machine and lock it every time you
leave it unattended. Return keys to authorized security.
Heed all shut-down operations of the Operation and
Maintenance Instruction Manual are followed. Every
time you leave the machine, engage parking brake (if
equipping unit).
MAINTENANCE
GENERALITIES
- Before operating or performing any intervention on the
machine:
- read carefully all the rules contained by this Manual;
- read and obey all safety related plates and instruc-
tions located on the machine.
- Do not allow unauthorized personnel to perform any
maintenance operation. Do not perform maintenance
operation without prior authorization. Follow all recom-
mended maintenance and service procedures.
- Keep operator’s compartment free of all loose objects
that are not properly secured.
- Do not wear rings, wrist watches, jewellery, loose or
hanging apparels, such as ties, torn clothing, scarves,
unbuttoned or unzipped jackets that can catch on mov-
ing parts.
Wear proper safety equipment as recommended for the
job. Examples: hard hat, heavy gloves, ear protection,
safety glasses or goggles, reflector vests, respirator.
Consult your employer for specific safety equipment
requirements.
- Do not use controls or hoses as handholds when climb-
ing on or off the machine. These components are mov-
able and do not provide a solid support. Controls may
also be moved unintentionally causing accidental ma-
chine or equipment movements.
- Do not jump on or off the machine. Keep two hands and
one foot, or two feet and one hand in contact with steps
and grab rails and handles at all times.
- Do not perform any service operation on the machine
with a person seated in the operator’s compartment,
unless he is an authorized operator co-operating in the
operation to be performed.
- Keep operator’s compartment, stepping points, grab-
rails and handles clear of foreign objects, oil, grease,
mud or snow accumulation to minimize the danger of
slipping or stumbling. Clean mud or grease from shoes
before attempting to mount or operate the machine.
- Keep shoes free of mud or grease before climbing or
driving the machine.
- Never attempt to operate the machine or its tools from
any position other than seated in the operator’s seat.
- When maintenance operations require moving hydrau-
lically operated attachments by means of machine’s
hydraulic system remember that all manoeuvres must
be made only when seated in the operator’s seat. Before
starting machine or moving attachment or tools, set
brakes, sound horn and call for an all clear. Raise
attachment slowly.
- Always block with external supportsany linkage or part
on machine that requires work under the raised linkage,
part or machine . Never allow anyone to walk under or
be near unblocked raised equipment. Unless your are
positively sure that total safe condition exist, avoid stay-
ing under raised equipment, even if blocked.
- Never place head, body, limbs, fingers, feet or hands into
exposed portions between uncontrolled or unguarded
scissor points of machine without first providing secure
blocking.
- Never perform interventions with engine running, ex-
cept as called for in a Manual. Do not wear loose clothing
or jewellery near moving parts.
- When servicing or maintenance require access to areas
that cannot be reached from the ground, use a ladder or
step platform that meet local and national regulations, to
reach the service point. If such ladder or platform are not
available, use the machine hand holds and steps as
provided. Perform all service or maintenance carefully.
- Shop and/or field service platforms or ladders must be
constructed and maintained in accordance with local
and national regulations.
- Disconnect batteries and TAG all controls according to
current regulations to warn that work is in progress. Block
machine and all attachments that must be raised accord-
ing to current regulations.
Due to the presence of flammable fluids, never check or
fill fuel tanks, batteries, nor use starting fluid near lighted
smoking materials or open flames.
- BRAKES ARE INOPERATIVE when manually released
for servicing. Provisions must be made to maintain
control of the machine by blocking or other means.
- The fuel filling nose must be kept constantly inside the
filling neck. Keep this contact from the beginning to the
end of the fuelling operation to avoid the possibility that
sparks due to static electricity are generated.
- Use only designated towing or attaching points. Use
care in making attachments. Make sure pins and/or locks
are secure before pulling. Stay clear of drawbars, cables
or chains under load.
IV

SAFETY RULES
V
- To move a disabled machine, use a trailer or a low-boy,
if available. In case towing is needed , use all necessary
signals required by local and national regulations, and
follow the directions provided in this Manual.
- To load/unload a machine from transporter, choose a
level surface ensuring firm support to the wheels of truck
or trailer.
Use strong access ramps, with adequate height and
angle. Keep surface free of mud, oil or slippery materials.
- Anchor the machine securely to the bed of truck or trailer
and block wheels or tracks with appropriate wedges.
- Never align holes with fingers or hands; always use
appropriate aligning tools.
- Eliminate all sharp edges and burrs from re-worked
parts.
- Use only approved grounded auxiliary power sources
for heaters, chargers, pumps and similar equipment to
reduce the hazards of electrical shocks.
- Lift and handle heavy parts with a lifting device of proper
capacity. Be sure parts are supported by proper slings
and hooks. Use lifting eyes if provided. Watch-out for
people in the vicinity.
- Never pour gasoline or diesel fuel into open, wide and
low containers. Never use gasoline, solvent or other
flammable fluid to clean parts. Use exclusively qualified,
non-flammable, non-toxic commercial solvents.
- When using compressed air for cleaning parts, use
safety glasses with side shields or goggles. Limit pres-
sure to 2 bar, in accordance with local and national
regulations.
- Do not run the engine in closed areas without proper
ventilation to remove deadly exhaust fumes.
- Do not smoke or permit any open flames or spark near
when re-fuelling or handling flammable materials.
- Do not use an open flame as a light source to look for
leaks or for inspection anywhere on the machine.
- Make sure that all mechanic’s tools are in good condi-
tions. NEVER USE tools with mushroomed heads or
frayed. Always wear eye protections.
- Move with extreme care when working under the ma-
chine, its attachments and or on or near them. Always
wear protective safety equipment as required, such as
hard hat, goggles, safety shoes, ear plugs.
- When performing operations requiring running of the en-
gine, have a qualified operator in the operator’s seat at all
times with the mechanic on sight. Place the transmission
inneutralandsetthebrakesandsafetylock.KEEPHANDS
AND CLOTHING AWAY FROM MOVING PARTS.
- For field service, move machine to level ground, if
possible, and block it.
If work on an incline is absolutely necessary, first block
machine and its attachments securely, than move it to
level ground as soon as possible.
- Do not trust worn and /or kinked chains and cables: do
not use them for lifting or pulling operations.
To handle them, always use heavy gloves.
- Avoid kinking chains or cables.
Do not pull through a kinked chain or cable to the high
stresses and possibility of failure of the kinked area.
Always wear heavy gloves when handling chains or
cables.
- Be sure chains and cables are anchored and the anchor
points are strong enough to handle the expected load.
- Keep exposed personnel clear of anchor points and
cables or chains.
- DO NOT PULL UNLESS OPERATOR’s COMPART-
MENT OF MACHINES INVOLVED ARE PROPERLY
GUARDED AGAINST POTENTIAL CABLE OR CHAIN
BACKLASH.
- Keep the area where maintenance operations are per-
formed CLEAN and DRY. Eliminate immediately all
water and oil spillages.
- Do not pile oily or greasy rags; they represent a fire
hazard. Store in closed metal container.
- Before starting machine, check, adjust and lock the
operator’s seat for maximum comfort and control of the
machine.
Be sure exposed personnel in the area of operation are
clear of the machine before moving it or its attachments.
Sound horn.
- Rust inhibitors are volatile and flammable Use only in
well ventilated areas.
Keep open flames away - DO NOT SMOKE - Store
containers in a cool well ventilated place, secure against
unauthorised personnel.
- Do not carry loose objects in pockets that might fall
unnoticed into open compartments.
- Wear proper protective equipment such as safety gog-
gles or safety glasses with side shields, hard hat, safety
shoes, heavy gloves when metal or other particles are
apt to fly or fall.
- Wear welders protective equipment such as dark safety
glasses, helmets, protective clothing, gloves and safety
shoes, when welding or burning.
Wear dark safety glasses near welding zones.
DONOTLOOKATARCWITHOUTPROPEREYEPRO-
TECTION.

- Know your jacking equipment and its capacity. Be sure
the jacking point used on the machine is appropriate for
the load to be applied. Be sure the support of the jack at
the machine and under jack is appropriate and stable.
Loads lifted by hydraulic jacks are always dangerous.
Transfer load to appropriate blocking as a safety meas-
ure, before proceeding with service or maintenance
work, according to local or national regulations.
- Steel cables are frayed after prolonged use; always
wear appropriate protections (heavy gloves, goggles
etc.).
- Handle all parts carefully. Keep hands and fingers away
from structures, gears or moving parts. Use and wear
always the appropriate protections
- Compressed air systems can have water deposits cre-
ated by moisture condensation due to changes of atmos-
pheric conditions. If required, discharge deposits, as
instructed.
STARTING
- Do not run the engine in closed areas without proper
ventilation to remove deadly exhaust fumes.
- Do not place head, body, limbs, feet, hands or fingers,
near rotating fans or belts. Be especially alert near
pusher fans.
- REMEMBERTHATSTARTINGFLUIDISFLAMMABLE.
Follow recommendations printed on containers and in
the Operation and Maintenance Manual.
- Containers must be stored in fresh, well ventilated
places, out of reach of unauthorised persons. Follow
strictly the instructions provided by the Manufacturer.
DO NOT PUNCTURE OR BURN CONTAINERS.
ENGINE
- Loosen the radiator cap very slowly, to release pressure
from the system, before removing it. All coolant level top-
ups must be performed with engine OFF.
- Avoid that flammable materials touch exhaust parts.
Should this be possible, provide the necessary protec-
tions.
- Do not run engine when refuelling and use care if the
engine is hot due to the increased possibility of a fire if
fuel is spilled.
- Never attempt to check or adjust fan belts when engine
is running.
SAFETY RULES
VI
- Do not adjust engine fuel pump when machine is mov-
ing.
- Do not lubricate the machine with engine running.
- Do not run the engine with air intakes, door or protections
open.
ELECTRICALSYSTEM
- Always disconnect batteries prior to any intervention on
machine or electrical system (cleaning, repair, mainte-
nance).
- Should booster batteries be used, remember to connect
both ends of the booster cables in the proper manner (+)
with (+) and (-) with (-). Avoid short-circuits of the termi-
nals. Follow thoroughly the instructions of this Manual.
- Before any intervention, make sure that the main switch
is OFF.
- BATTERYGASISHIGHLYFLAMMABLE.Leavebattery
box open to improve ventilation when recharging batter-
ies. Never check charge by placing metal objects across
the posts. Keep sparks or open flames away from batter-
ies. Do not smoke near battery to guard against the
possibility of causing an explosion.
- Before any intervention, make sure that there are no fuel
or electrolyte leakages; eliminate them before proceed-
ing with further work.
Do not charge batteries in closed areas: ensure enough
ventilation to prevent the possibility of accidental explo-
sions due to accumulation of gases generated during
the recharging.
HYDRAULICSYSTEM
- Fluid escaping under pressure from a very small hole
can be almost invisible and can have sufficient force to
penetrate the skin. Use a piece of cardboard or wood to
search for suspected pressure leaks.
DO NOT USE HANDS. If injured by escaping fluid, see
a doctor at once. Serious infection or reaction can
develop if proper medical treatment is not administered
immediately.
- Stop the engine and release all pressures in the system
before removing panels, housings, plugs or covers.
- In case pressures must be measured, use instruments
of adequate capacity. Always follow the recommended
procedures.

SAFETY RULES
VII
TOOLS
- Keep head, body, limbs, feet, fingers or hands away from
bucket, blade or ripper when in raised position.
- Prior to any intervention, install all safety devices accord-
ing to current rules and regulations. In case equipment
on the machine must be operated by hydraulic systems,
remember to proceed only after seating in the operator’s
compartment.
Make sure that there are no persons in the operating
area of the machine. Alert people before operating using
the horn and by voice. Move the equipment very care-
fully.
- Do not use machine to transport loose objects, unless
proper devices for this purpose are provided.
WARNING
On machines having hydraulically, mechanically, and/or cable controlled equipment (such as shovels,
loaders, dozers, excavators etc.) be certain the equipment is lowered to the ground before servicing,
adjustingand/orrepairing.Ifitisnecessarytohavethehydraulically,mechanically,and/orcablecontrolled
equipment partially or fully raised to gain access to certain items, be sure the equipment is suitably
supported by means other than the hydraulic lift cylinders, cable and/or mechanical devices used for
controlling the equipment.
- Clutches and brakes of this machine and eventual
auxiliary equipment and attachments (such as operat-
ing cylinder or winches control valves) must always be
properly adjusted in accordance with the instructions
provided by the Manuals of the Manufacturer. Never
perform adjustments with engine running, except when
called for by the above instructions.
- Do not proceed with adjustments with engine running,
unless required by prescribed procedures.
- When changing work shifts, check that there are no
screws and/or mounting brackets loose. If required
tighten as instructed in this publication.

SAFETY RULES
SAFETY RULES FOR SEALS
VITON SEALS (fluoro - elastomer)
Seals, especially Viton made O-rings Normally coloured
red) are used in systems operating at high temperatures,
considering the resistance of this material to the effects of
heat. However, should this material be subject to tempera-
tures exceeding 315 °C (600 °F) - in practice only in case
of a fire or subject to the flame of an oxyacetylene torch -
hydrofluoric acid is generated. This acid is highly corro-
sive and can cause severe burns if in contact with the
skin.
every time it is necessary to intervene on components
equipped with Viton rings, and there is the suspicion that
they have been exposed to excessive temperatures the
following procedures must be applied:
1) inspect visually, without touching them, all seals that
appear to be damaged by excessive heat. They appear
black and sticky;
2) check the type of material of the seals to identify if they
are made with Viton, performing the test illustrated in
the enclosure, on spare parts;
3) if it was found or there is a reasonable doubt that Viton
made components are involved, the contaminated
area MUST be decontaminated prior to proceeding
with further operations;
4) wear neoprene or PVC gloves and protective glasses
or face shield, wash accurately the contaminated area
with a solution of water lime (available at tile stores)
dissolved in water until a milky looking liquid is ob-
tained. Rinse accurately with steam or running water;
5) eliminate the materials removed and the protective
gloves in safe manner avoiding burning them.
TEST TO DISTINGUISH RUBBER MATERIAL (BUNA N) FROM
"VITON" (FLUORO ELASTOMER)
WATER WATER
"VITON"
FLUORO ELASTOMER
SINKS
NITRIL RUBBER / BUNA N
FLOATS
VIII
TRICHLOROETHYLENE

TECHNICAL DATA TABLES
D255
CRAWLER DOZER

0 - 1D 255
Carefully read personal and machine SAFETY PRECAUTIONS at the beginning of this Manual
NOTE: - MACHINE IN OPERATING CONDITIONS
- HEIGHT OF GROUSERS: 71.4 mm
- The figure includes optional tools
ANGLEDOZER
2070
3420
460
2296
2315
1500
175
800
700688
5301220
±5° 30'
±10°
1300560
700
1100
4490
4465
2973
550
5415
5855
4460 5360
5800
BULLDOZER HSU + RIPPER
L. 502
2770
2940
3800

0 - 2 D 255
Overall lenght (bare tractor) mm 4 490
Overall lenght (with semi-U blade) mm 5855
Overall lenght (with angledozer blade) mm 5 800
Overall width (bare tractor) mm 2 940
Overall width (with semi-U blade) mm 3650
Overall width (with angledozer blade) mm 4 460
DIMENSIONS
Overall height (to tip of exhaust pipe) mm 3 400
Overall height (with ROPS cab) mm 3 420
Track gauge mm 2 070
Minimum distance from ground mm 460
Lenght of track on ground mm 2 973
Track shoe width mm 550
Shipping weight (including ROPS cab, blade lift cylinders, kg 21 845
lubricants, coolant, 10% fuel)
MASS
Operating weight with semi-U (HSU) blade and ROPS cab kg 27000
Operating weight with angle (HA) blade, ROPS cab and ripper kg 26 400
Fwd 1st
km/h 3.7
Fwd 2nd
km/h 6.1
Fwd 3rd
km/h 10.9
SPEEDS
Rev 1st
km/h 4.4
Rev 2nd
km/h 7.2
Rev 3rd
km/h 12.6
Inside cab standard (Lpa) ISO 6394 dB 83
CEE 86/662 dB 83
NOISE LEVEL
Outside (Lwa) ISO 6394 dB 113
CEE 86/662 dB 113
PERFORMANCE
(Track shoes width 550 mm)
With semi-U (HSU) blade and ROPS bar 0.8085
GROUND
PRESSURE With angle (HA) blade, ROPS cab and ripper bar 0.791
With semi-U (HSU) blade, ROPS cab
and ripper bar 0.910
GRADEABILITY (1st
speed) degree 45

0 - 3D 255
Model CUMMINS 6CTAA8.3
Type Diesel, 4 - cycle, direct injection,
turbocharged, aftercooled
Bore x stroke 114 x 135 mm
Displacement 8268 cm3
Number of cylinders 6
Net flywheel power (SAE J1349) 177 kW at 2200 rpm
Net flywheel power (DIN 6270) 240 CV / 179 kW at 2200 rpm
Net flywheel power (ISO 9249) 177 kW at 2200 rpm
Net flywheel power (CEE 80/1269) 177 kW at 2200 rpm
Max torque 114,6 daN m (101 kgm) at 1400 rpm
Governed speed 2200 rpm
Low idling 890 rpm
Fuel consumption ratio (max torque) 205 gr / kWh
Cranking motor 24 V - 7.5 kW
Alternator 28 V - 65 A
ENGINE Battery 12 V - 180 Ah x 2
Radiator Air - water with tubes
and line cores
Core size 1090 x 874 x 114 mm
Radiator cap pressure 0.75 bar
Fan Blower steel sheet, 7 blades,
diameter 900 mm
Air cleaner Dry type, two state with safety element
and centrifugal separator,
restrictor indicator
Muffler Horizontal type with dust ejector,
dimensions 258 x 545 mm
Aftercooler Air - air with tubes
and line cores
Core size 552 x 555 x 82 mm - Aluminium
ATH -100 °C
Air flow 23 kg/min
Max pressure 4 bar
Fan diameter 500 mm
1 stage, 1 fase, diameter 16"
Stall ratio 3.28 : 1
Impeller shaft moves thru a set
of gear:
Torque converter – implement pump
– transmission pump + converter pump
+ oil recovery pump
– steering clutches pump
POWER TRAIN
SYSTEM Countershaft, full power shift with remote
hydraulic pilot control, 3 gears forward and
3 gears reverse obtained through 5 multidisc
clutches actuated by single piston.
Transmission Transmission with 3 clutches having
centrifugal valves.
FWD and REV modulating valves, speeds
engagement modulating valve.

0 - 4 D 255
Torque converter - transmission Combined with converter oil circulation pump
pump and oil recovery pump
Capacity (2100 rpm) 96.5 l/min
Rated pressure 14 bar
Full flow (including lubrication) 193 l/min
Suction Metal gauze and magnetic rod 100 micron
Transmission filters filter capacity, without by-pass
Return Paper type with by-pass valve
Transmission regulating valve Mounted on converter case
Relief valve pressure (at 10 l/min flow) 10 ± 0.5 bar
Safety hand lever valve In lock position inhibits the gear engagement
and the engine cranking, and applies the
parking brakes
Pilot control valve (manipulator) On - off type with hydraulic detents.
Semi-open pattern.
Position 3FWD 2FWD 1FWD
– N N
3REV 2REV 1REV
POWER TRAIN Drive shaft Two U-joint and telescopic shaft type
SYSTEM
Nominal lenght 256 mm
Power take - off provvision Output from transmission reverse gear shaft.
CW rotation, viewed from the rear side of the
machine
Max output torque capacity (@ 0 output rpm) 241.5 daN m
Max output speed (@ 0 output torque) 2277 rpm
N. of splines 24
Module 2.58
Bevel gear set Straddle mounted pinion. Modular assembly
Ratio 13 / 38 = 1 : 1.293
Steering clutch Multidisc, wet type, spring actuated,
hydraulically released
N. of friction discs 11 (each clutch)
Total single friction area 7612 cm2
Disc I.D. 280 mm
Disc O.D. 350 mm
Friction material Sinterized

0 - 5D 255
Brake Wet, Single band, bi-directional.
Brake mechanism is actuated by a spring
and released by the transmission oil
system, in the braking operation.
It is actuated by steering system during
the steering operation.
The band wear is recovered with automatic
adjuster device. Warning output light for
excessive wear.
Drum diameter 406 mm
Band width 130 mm
Total friction area 1604 cm2
Final drive Countershaft double reduction
Ratio 1 : 12.410
Sprocket 9 bolt-on segment type
Total N. of teeth 27
POWER TRAIN Pitch diameter 936.62 mm
SYSTEM
Tooth width 95 mm
Steering and braking control system The steering system is operated by two
hand levers installed on the left side of the
operator compartment. The lever travel,
applies a modulated pressure in the
steering control valve obtaining two
proportional pressures. First pressure
operate the disengagement of steering
clutch. Second pressure is equal to zero
until the first pressure reaches 17.5 bar
(50% of lever travel) than applies positively
the steering brakes. The service brake
system is operated negatively by a brake
pedal. Pedal acutation cuts with
modulation the back pressure of the brake
piston and applies, with springs, the brakin
load.
Steering system pump Gear type
Flow (@ rated engine speed) 65.5 l/min
Rated pressure 38 ± 38.7 bar
Suction Metal gauze and magnetic rod 100 micron
Steering system filters filter capacity, without by-pass.
Return Spin on type with by-pass valve 10 micron
filter capacity.

0 - 6 D 255
RAISE
NEUTRAL
LOWER
+ FLOAT
(w/DETENT)
Track frames Box section type, oscillating beam is
supported by resilient pads on the forward
portion of the track frame.
Rear of track frame pivots about sprocket
shaft.
Track oscillation (total travel of idler wheel) 410 mm
Lubrication system Rollers, idlers, sprocket, pins and bushing,
sealed and permanently lubricated.
TRACK Idlers With hydraulic track adjuster
Carrier roller (each side) 2
Track roller (each side) 7
Track shoe 550 mm (600 mm - 700 mm) Assembly type single grouser, 41 on each
side.
Grouser height 71.4
Link pitch 216 mm
Type Gear type
MAIN HYDRAULIC Capacity at governed
PUMP speed 2121 l/min
Relief valve pressure 190 bar
Type Three spools
Lower - raise - float control.
Blade left and right tilt control.
Available for rear additional implement
control.
MAIN CONTROL
VALVE Specifications Tandem circuit, flow reduction valve on
tilt circuit.
Capacity 70 l/min (nominal), safety valves
on each circuit.
IMPLEMENTS
HYDRAULIC
SYSTEM
FRONT
IMPLEMENT Functions
SINGLE
CONTROL LEVER
HYDRAULIC Type Box type. Joint with fuel tank.
TANK
LH TILT RH TILT
LH TILT RH TILT
LH TILT RH TILT

0 - 7D 255
Suction Immersed in tank, metal gauze and 250
micron filter capacity, with by-pass
(pressure cal. 0.2 bar).
HYDRAULIC
TANK FILTERS Return Immersed in tank, microfiber type and 10
micron filter capacity with by-pass
(pressure cal. 2.5 bar).
Type Double acting. Stroke end valves and
IMPLEMENTS quick drop valves on cylinders heads.
HYDRAULIC
SYSTEM Cylinder bore 110 mm
Piston stroke 1302 mm
LIFT Outiside diameter of
CYLINDERS piston rod 63 mm
Max. distance
between pins 1982 mm
Min. distance
between pins 980 mm
Type Multiple box section with lower reversible
cutting sectors and lower edge reinforced
with ribbings.
Blade support Brace type (tilt cylinder on right).
Equistatic device for uniformstress
distribution on push beams.
.
Blade width 3800 mm
DIMENSIONS
Blade height 1500 mm
Max. lifting height
from ground 1220 mm
Max. lowering depth
from ground 530 mm
Max. tilt 800 mm
IMPLEMENT PERFORMANCE
(BULLDOZER) Cutting angle range 5° 30'
Moldboard volume 7 m3
Raising average
velocity (2100 rpm) 0.371 m/s
Type Double acting
Cilynder bore 160 mm
TILT - HYDR.
CYLINDER Outside diameter of 80 mm
(BULLDOZER) piston rod
Max. distance 1150 mm
between pins
Min. distance 1010 mm
between pins

0 - 8 D 255
Type Hydraulic angledozer.
Multiple box section with lower reversible
cutting sectors and lower edge reinforced
with ribbings.
Blade support C - frame, welded box section.
.
Blade width 4460 mm
DIMENSIONS
Blade height 1100 mm
Max. lifting height 1300 mm
from ground
Max. lowering depth 560 mm
from ground
Max. tilt 700 mm
PERFORMANCE
Cutting angle range 5°
IMPLEMENT Moldboard volume 4.1 m3
(ANGLEDOZER)
Raising average
velocity (2100 rpm) 0.394 m/s
Type Double acting
Cilynder bore 140 mm
TILT - HYDR.
CYLINDER Outside diameter of 80 mm
(BULLDOZER) piston rod
Max. distance 1569 mm
between pins
Min. distance 1445 mm
between pins
Type Parallelogram type ripper PD20 two dou-
ble acting cylinders. Cylinders support
and tool beam in box section weld fabri-
cated structure (three positions adjust-
able)
N. of shanks 3
Bore x piston rod diameter 125 x 70 mm
IMPLEMENT
(RIPPER) Stroke 590 mm
Closed lenght 1015 mm
Extended lenght 1605 mm
Penetration force 48150 daN

0 - 9D 255
MASS
Engine assembly 1230 kg
Radiator assembly 140 kg
Fuel and hydraulic tank assembly 320 kg
Rear transmission housing 3953 kg
Steering control valve assembly 10 kg
Torque converter assembly –
Transmission assembly 726 kg
Final drive assembly (each side) –
Hull frame assembly 2000 kg
Track frame (each side) 1070 kg
Idler assembly (each side) 230 kg
Track roller assembly (single board) 18.5 kg x 5
Track roller assembly (double board) 19.3 kg x 2
Carrier roller assembly 52 kg x 2
Track shoe assembly (each side) 550 mm wet type 1910 kg
Main control valve assembly 37 kg
Engine flap door 31 kg
Transmission underguard (front) 40 kg
Transmission underguard (rear) 41 kg
Gear box underguard 30 kg
Straight tildozer assembly 1340 kg
Blade angle 1810 kg
Blade HSU 2090 kg
C - frame angle 1460 kg
Tilt cylinder assembly 170 kg
Blade lift cylinder assembly 180 kg x 2
Cab assembly 650 kg
Rops support 644 kg
Battery (each) 49 kg

0 - 10 D 255
FLUIDS AND LUBRICANTS
REFILL
(International
classification)
FLUIDS AND
LUBRIFICANT
AMBRA
AGRIFLU (50%)
Q.TY
(Liter)
65
495
18
82
67
100
43
9
–
0.5
AMBIENT
TEMPERATURE
(C°)
–
VISCOSITY
NOTE: Oil quantities indicated are those required for periodical changes.
If fuel sulphur content is over 0.5% change engine oil as follows:
% sulphur Periodic change
0.5 to 1.0% Half normal interval
Over 1.0% Quarter normal interval
ITEM
COOLING
SYSTEM
FUEL TANK
ENGINE
BEVEL GEAR
STEERING CLUTCHES
BRAKES
CONVERTER AND
TRANSMISSION
EQUIPMENT
HYDRAULIC SYSTEM
FINAL DRIVES
(each)
TRACK IDLERS
AND ROLLERS
GREASE FITTINGS
CAB
TILTING
SYSTEM
50-50 mixture of water
coolant. Has adequate
protection against:
xidation foaming,
corrosion, scaling
and freezing down
to -35 °C
Agriflu mixed
with 50% water
protects down
to -35 °C
–
Diesel fuel ASTM
No. 2-D type TT
of good quality
and brand
–
MasterGold HSP
SuperGold
API CH-4 ACEA E5
API CF-4 MIL-L-2104 E
SAE 15W-40
SAE 10W-30
SuperGold
API CF-4
MIL-L-2104 E
SAE 10W-30
Hydropower
ATF type A SUFFIX A
ALLISON C4
SAE 10W
Hydrosystem 46HV
or
Hi-Tech 46
DIN 51524/2 HVI ISO VG 46
HYPOIDE 90
API GL5
MIL-L-2105
SAE 80W-90
SuperGold
API CF-4
MIL-L-2104 E
SAE 15W-40
SAE 10W-30
GR9
N.L.G.L.2,
EP LITHIUM/CALCIUM
–
Hydropower
ATF Type A SUFFIX A
ALLISON C4
SAE 10W
-15 °C ÷ +40 °C
-25 °C ÷ +20 °C
-20 °C ÷ +20 °C
-20 °C ÷ +40 °C
-20 °C ÷ +40 °C
-20 °C ÷ +40 °C
-15 °C ÷ +40 °C
-25 °C ÷ +20 °C
–
-20 °C ÷ +40 °C
–

0 - 11D 255
STANDARD PERMISS.
VALUE VALUE
Nominal idling speed (50 hour break-in) 2200 rpm –
High idling speed (50 hour break-in) 2460 rpm ± 50
ENGINE Low idling speed (50 hour break-in) rpm ± 50
SPEED
Converter stall (50 hour break-in) rpm -100
Implement stall (50 hour break-in) rpm -100
Stall (50 hour break-in) rpm -100
MAX 3.4 bar ± 0.5
Oil pressure At governed speed
ENGINE MIN 0.68 bar ± 0.5
LUBRICATION
SYSTEM Oil temperature all speed 90 - 121 °C 130
Max oil flow 2200 rpm 8 l/min –
Oil temperature 70°
Intake resistance At rated speed and full load 450 mm H2
O 625
Exhaust pressure At rated speed and full load 76 mm Hg –
Exaust 2000 rpm 497 °C –
temperature (intake air temperature 20 °C)
Smoke (Bosh scale rated
speed rpm) 0.81 3.5
INTAKE AND (Bosh scale max
EXHAUST torque rpm) 1 5
SYSTEM
Emissions (ISO8187 without fan
Grade of smoke and turbocharger)
NOx 6.0 g/kWh 6.0
CO 3.5 g/kWh 3.5
HC 1.0 g/kWh 1.0
Powder emission 0.2 g/kWh 0.2
Fan speed At rated engine speed 1328 rpm -30
COOLING Radiator Opening pressure 0.7 bar ± 0.15
SYSTEM pressure valve
Fan belt (Dynamometer value) 65 - 70 daN 62
tension
SETTING VALUES AND TESTS
Note – The values in the table are referred to engine on test bench.

0 - 12 D 255
STANDARD PERMISS.
VALUE VALUE
Fuel injection + 8
FUEL pressure Nozzle tester 260 bar 0
SYSTEM
Fuel injection timing Before top dead center 23° 23° ± 30'
TORQUE Engine low idling 0.5 bar ± 0.1
CONVERTER
OUTPUT PRESSURE Engine high idling 3.5 bar ± 1.5
Transmission pressure (at 10 l/min flow) 13.7 bar ± 0.5
(at 66 l/min flow) 17.0 bar ± 0.5
1st
14 ÷ 15.5 bar ± 1
Forward 2nd
14 ÷ 15.5 bar ± 1
3rd
14 ÷ 15.5 bar ± 1
TRANSMISSION
OPERATING 1st
14 ÷ 15.5 bar ± 1
PRESSURES Reverse 2nd
14 ÷ 15.5 bar ± 1
3rd
14 ÷ 15.5 bar ± 1
Neutral (single clutch) 4 ÷ 5 bar ± 0,5
Engine low idling 0.35 ÷ 1.4 bar +0.5 -0.2
Lubrication
Engine high idling 1.7 ÷ 2.5 bar ± 0.5
Max. pilot pressure 38 bar ± 2
Max. clutch pressure 35.5 bar ± 2
STEERING Max. brake pressure 24 bar ± 3
CONTROL VALVE Pilot pressure @: Start of clutch
PRESSURES pressure 2.5 bar ± 0.5
Start of brake
pressure 18.5 bar ± 1
STEERING Pilot pressure: Start (@26% lever travel) 11 bar +0.5
MANIPULATOR Limit (@96% lever travel) 32.5 bar +2
PRESSURE SETTINGS Max. (@full lever travel) 38 bar ± 2
Brake pressure Brake pedal travel %
BRAKE
VALVE Up to 32 ± 42% 15 bar ± 1
PRESSURE @ 32 ± 42% 11 bar ± 1.5
SETTINGS @ 68 ± 78% 6.5 bar ± 1,5
From 68 ± 78% to 100% 0 bar –
Operating pressure at governed speed 185 ÷ 195 bar ± 5
WORK EQUIPMENT
HYDRAULIC Max. pressure valves Principal 190 bar ± 7
SYSTEM calibration (flow 50 l/min, Secondary A1 230 bar ± 5
CALIBRATION oil temperature Secondary B1 230 bar ± 5
80 °C) Secondary A2 230 bar ± 5
Secondary B2 230 bar ± 5

0 - 13D 255
STANDARD PERMISS.
VALUE VALUE
Flow control valves 55 ÷ 70 l/min 50 ÷ 75
(tilt section)
Blade Handle stroke (lift) 105 mm 105
Handle stroke (tilt) 110 mm 110
TRAVEL OF
CONTROL Ripper Handle stroke 105 mm 105
LEVERS
Fuel control On engine 54° ± 8
On dashboard 20° +5
Decelerator pedal Center of pedal 29° 29
Brake pedal Full stroke 78.5 mm ± 10
Hold raise 3 daN 3.5
Blade lever (center Hold lower 3 daN 3.5
OPERATING of lever knob) Engaged float 9 ÷ 11 daN 12
FORCE OF Disengaged float 3.5 ÷ 6.5 mm 7
CONTROL
LEVERS Ripper control lever Hold raise 3 daN 3.5
(center of lever
knob) Hold lower 3 daN 3.5
Blade lift
(Bull conf.)
Raise 3.4 sec 4
Lower 1.6 sec 2.5
WORK
EQUIPMENT
SPEED
Blade lift
From right tilt to left tilt 3.1 sec 3.5
From left tilt to right tilt 2.2 sec 2.5

0 - 14 D 255
STANDARD PERMISS.
VALUE VALUE
Raise 2.2 sec 3
WORK
EQUIPMENT Ripper lift
SPEED
Lower 1.3 sec 2
Lift up the front of the machine, operating the
WORK lower control blade.
EQUIPMENT Maximum re - enter of blade lift cylinders: 5.6 mm/min 10
DRIFT
(Oil SAE 10 - 60 °C,
engine off)
Lift up the blade to max height.
Maximum lift cylinder extension: 8 mm/min 10

0 - 15D 255
STANDARD PERMISS.
VALUE VALUE
Beginning from blade lay down,
operate the right tilt control lifting
up to maximum height the left
side of the machine.
Max re - enter of tilt cylinder: 5 mm/min 10
Beginning from blade lay down,
operate the left tilt control lifting
WORK up the right side of the machine.
EQUIPMENT Max re - enter of tilt cylinder: 8 mm/min 10
DRIFT
(Oil SAE 10 - 60 °C,
engine off)
Lift up the machine to maximum height
operating the ripper lower control.
Maximum cylinder extension: 1 mm/min 5
Lift up the ripper to maximum height
operating the ripper lever control
Maximum cylinder extension: 1 mm/min 5

0 - 16 D 255
GENERAL INSTRUCTIONS
INSTALLATION OF SHAFT SEALS
Follow these cautions:
- priortoinstallation,soakthesealsforatleasthalfan
hour in the same oil in which they will operate;
- thoroughly clean the shaft and ensure that the
contact surface is undamaged;
- position seal lip toward the fluid; if thrower lip type,
positionthegroovessothatduringshaftrotationthe
fluid is thrown back;
- smear the sealing lip with a thin film of lubricant
(oil is better than grease);
- installthesealintoitsseatbypressingorusingaflat
ended punch; on no account use hammers;
- avoid pushing the seal into its seat in a tilted
position. After installation, ensure that the seal is
pressed fully home;
- topreventsealinglipdamageduringinstallation,use
some sort of protection between seal and shaft.
INSTALLATIONOFO-RINGS
Lubricate O-rings before installation and do not twist
them when installing, otherwise leakages will occur.
REMOVAL/INSTALLATION OF FACE SEALING
RINGS
To remove, proceed as follows:
- press one end of the ring into its seat (a);
- holdringinpositionandinsertascriberpointbeneath
the other side to separate the interlocking ends, as
shown in figure (a);
a
To install, proceed as follows:
- press one end of ring against the inner face of the
seat (b);

0 - 17D 255
- holdringinthispositionandliftthefreeend(b)until
the two teeth lock correctly (c).
Many repair and service shops use caustic com-
pounds to remove grease, dirt, paint or remains of
gasketsetc.fromcomponents.Thesecompoundsare
extremely useful and effective if used correctly, but
may cause considerable damages to certain materi-
als.
Materials such as alluminum, rubber, fibres, sintered
bronzeandbindingagents,areparticularlysensitiveto
all high-concentration caustic compounds.
Certainheatexchangershavealuminumfins.Toclean
bothinsideandoutsideoftheseparts,werecommend
the use of solvents that do not react with aluminum.
DISASSEMBLY
When operating on the engine or on other units re-
movedfrommachine,alwaysuseappropriatestands.
Placesmallitemsremovedfrommachineinappropri-
atecontainers.Becarefulnottodamagethemachine
surfacesofcomponentsandrestthem,afterremoving
them, on shelves or on wood blocks.
When removing alike components, such as valves,
tappetsetc.,placetheminsuitablecontainerstoavoid
incorrectre-reassembly.
ASSEMBLY
Carefully clean all parts to be refitted as described in
the Manual.
Theuseofspecialtoolsasspecifiedisrecommended.
Note – For the application of adhesive sealing com-
pounds, refer to the instructions of the different com-
mercial products.
The manufactured recommends, if not otherwise
indicated, the following adhesive seals: VIT Type
C, or RHODORSIL CAF 1, or LOCTITE 510.
b
c
ADVICEFORDISASSEMBLYANDREASSEMBLY
OFGROUPS
The following general information is aimed at facilitat-
ing disassembly and reassembly of groups.
Readwithattentionandfollowwhenperformingrepair
operations.
CLEANING
After disconnecting the electrical system, thoroughly
cleanthepartstobedisassembledwithajetofsteam.

0 - 18 D 255
Whenever possible, drive bushings in to their correct
position using a press. If it is necessary to use a
hammer to install the bushing, employ a suitable
punch to prevent any damage.
Lubricateballbearingsbeforeassemblyandbushings
prior to installing them. Lubricate the sealing lip on
seals before installation.
Whenever possible, use new seals. Cylinder head
gaskets must always be renewed.
Use screws with dimensions and specifications indi-
cated, making reference to part numbers in the Parts
Catalog.
Where shown, use safety washers, cotter pins, lock-
ing wires etc.
Respect specified torque loads as indicated in the
appropriate section of this Manual, using suitable
torquewrenches.
Self-locking nuts should be replaced every time a
disassemblyoperationisperformed,toensureagood
tightening.
HIGHPRESSUREPIPING,FITTINGS,HOSESAND
PIPES
This section contains recommendations and proce-
dures to be followed for the installation of pipings and
fittings.
- Keep all inside threads clean.
- Removetheplugsjustbeforeconnectingthepiping
and close immediately all free openings.
- Neveruseorre-usehalf-flangesout-of-shapemore
than0.6mm(0.023in)inthecenter(seeillustration).
- Check that the O-Ring seats are not damaged.
- Lubricate the O-rings.
- Check that the O-rings are placed in their seats.
- Tighten in a uniform way, to avoid bending or
damages to O-rings.
- Install pipings and supporting clamps letting them
slightly loosen (tighten the clamps after tightening
the connections).
- Check that pipings can match the part to be con-
nected, without forcing into position.
- If a pipe or hose is mounted straight, allow enough
space to absorb contractions caused by pressure.
- Pipingsshallnotbetwisted(seeillustration)ortouch
each other or other parts, especially moving parts.
Wrong Correct

0 - 19D 255
- Checkthatclampsizesarecorrectbyreferringtothe
diameterofthepipetobefastened,toavoidpossible
wear (see illustration).
- Do not mount clamps on a curve with a minimum
radius (under pressure, possible efforts arise in the
pipe; see illustration - the dashed lines indicate the
contraction that is caused by pressure).
Wrong Correct
- Ensure that clamps are fitted in the correct position,
to keep pipings away from contacts (see figure).
Correct
Wrong

0 - 20 D 255
NBR
FPM
EPDM
MVQ
NITRILE BUTADIENE
FLUOROCARBONIO
(VITON)
ETILENE PROPILENE
SILICONE
- 40 ÷ 120 °C
- 30 ÷ 125 °C
- 40 ÷ 200 °C
- 40 ÷ 150 °C
-60 ÷ 200 °C
MINERAL OIL AND GREASE,
COOLING FLUIDS, FUEL, WATER UP
TO 70 °C, AIR UP TO 110 °C
SAME COMPATIBILITY OF NBR 60 ÷
75 IRHD, BETTER RESISTANCE TO
EXTRUSION, USED ONLY AS STATIC
SEAL
FUELS, NON-FLAMMABLE FUIDS,
ACIDS, SOLVENTS, MINERAL OIL.
TO BE USED WITH TEMPERATURES
>100 °C
BRAKE FLUID (DOT 3) STEAM, HOT
WATER, SILICONE OIL AND GREASE.
WARNING: DO NOT USE WITH
MINERAL OIL OR GREASE
AIR, HOT WATER, HIGH ANILINE
POINT MINERAL OIL, STEAM, USED
ONLY AS STATIC SEAL
DESIGNATION ELASTOMER BASE TEMPERATURE FIELD OF USE
OF OPERATION
(*)
O-RING CORRECTLY O-RING UNDER EXTRUSION FRACTURE
INSTALLED PRESSURE OF O-RING OF O-RING
O-RINGS - Fields of use
Note –
(*) Temperatures applicable for static applications, provided as an indication.

0 - 21D 255
DIAGNOSTIC CHECKS
GENERAL
For a quick trouble diagnosis, the following rules are
recommended:
a) Knowing the machine.
Itisnotpossiblethetrouble-shootingandformulation
of diagnosis without a good knowledge of the ma-
chine.
A thorough reading of the descriptions contained in
theRepairManual,aboutthecompositionandopera-
tion of the various groups is recommended.
b) Check with the operator
Many troubles are caused by wrong use or lack of
maintenance. Check with the operator whether the
machinehadsimilartroublespreviouslyandwhether
corrective interventions have been performed with
appropriatetoolsandgenuinespareparts.Checkalso
ambient and working conditions of the machine and
how normal maintenance is performed.
c) Test the machine.
The best way to check the machine conditions is to
test it in real working conditions. Check:
- correct operation of monitoring instruments;
- performance of the machine;
- possible smells or signs of overheating;
- abnormal noises; check their origins and the work-
ing conditions in which they occur.
d) Machineinspection.
After step c is completed stop the machine and
perform a visual inspection. Check for possible leak-
ages, loosen screws defects or deformations etc.
e) Diagnosis
Once a trouble has been identified, make a list of the
possible causes, with the help of the corresponding
section,andfindthecorrectonebymeansofpractical
tests, beginning from the most probable causes and
the easiest to be performed.

0 - 22 D 255
multiply by to obtain
Force kg 0.9807 daN
Pressure kg/sqcm 0.9807 bar
Torques kg m 0.9807 da Nm
UNITS OF MEASURE
TheunitsofmeasureofthisManualarethoseusedby
theInternationalSystemandsupersedesthoseofthe
M.K.S.
Force: decanewton(daN)supersedeskilogram
(kg)
Pressure: bar supersedes kg/sqcm
Torque: decanewton x meter (daNm) super-
sedes kg m
To convert units of measure, use this table:
Note – For common repair use, the following
correlations are considered valid:
kg = daN; kg/sqcm = bar; kg m = da Nm.
CLASSIFICATION OF STANDARD PARTS FOR
TORQUEDETERMINATION
NOTE – If in the different sections torque values are
not specifically indicated, refer to “TIGHTENING
TORQUES” after identifying exactly the part.
The part is identified by a eight-digit code number.
Example:
I - Standard index number
Itisalwaysrepresentedbydigit1.Thisnumbermeans
that the part can be made in different versions,
differing for material and coating.
a - b - c - d - e - Standard base number
It is a number always made of five digits indicating the
dimensional features of the part.
f - Material index number
This digit indicates the material that is specified for a
certain part. The meaning is explained in the table
below.
g - Coating index number
This digit indicates the coating that is specified for
each part.
For the conversion of measure units from the
International System into British System, please refer
to the table below:
multiply by to obtain
Mass kg 2.205 Ib
Lenght mm 0.03937 in.
Pressure bar 14.5 p.s.i.
Torque daNm 7.373 lb.ft
Capacity l/min 0.2199 USG/min (UK)
0.2641 USG/min (US)
I / a b c d e / f g

0 - 23D 255
Strenght class and type of material
Material
index No. ( f )
CNH UNI DIN SAE BSI BNA
0
1
2
3
4
5
6
7
R 40
R 50
R 80
R 100
Ottone
Aluminium
Rame
D - 4S - 4A
5S - 6S
8G
100 10K
Ottone Messing
Aluminium Aluminium
Rame Kupfer
1
3
5
8
Brass
Aluminium
Copper
A
P
T
V
Brass
Aluminium
Copper
42
56
80
100
Laiton
Aluminium
Cuivre
Free for other metals
WARNING
- Lubricate screws and nuts with engine oil up to 24
mm diameter; for larger diameters use tallow.
- Tolerance on tightening torques is ± 5%.
- Strength classes R80, R100, R120, must be
considered as follows:
10.9 supersedes R 100
screws
12.9 " R 120
10 supersedes R 80
nuts
12 supersedes R 100
CDT = cadmium plated;
FOSF = phosphate plated;
ZNT = zinc plated.
}
}
TIGHTENINGTORQUETABLES
If the tightening torque of screws and nuts is not
specifically indicated in the single sections, refer to
the tables of the following page:

0 - 24 D 255
normal
daNm
Diameter
and pitch
mm
Self-locking
ZNT
daNm
normal
ZNT
daNm
Diamter
and pitch
mm
low type
daNm
low type
daNm
with polyamide ring
normal
daNm
M6 x 1
M8 x 1.25
M10 x 1.25
M10 x 1.5
M12 x 1.25
M12 x 1.75
M14 x 1.5
M14 x 2
M16 x 1.5
M16 x 2
M18 x 1.5
M18 x 2.5
M20 x 1.5
M20 x 2.5
M22 x 1.5
M22 x 2.5
M24 x 2
M24 x 3
M27 x 2
M30 x 2
M33 x 2
M36 x 3
1.3
3.2
7.2
6.5
13
11
19.5
18
30
-
45
-
60
-
80
-
100
-
95
130
170
220
-
3.2
6.2
6
10.2
9.6
15
14.6
20
-
29
-
35
-
-
-
52.5
-
-
-
-
-
M6 x 1
M8 x 1.25
M10 x 1.25
M10 x 1.5
M12 x 1.25
M12 x 1.75
M14 x 1.5
M14 x 2
M16 x 1.5
M16 x 2
M18 x 1.5
M18 x 2.5
M20 x 1.5
M20 x 2,5
M22 x 1.5
M22 x 2.5
M24 x 2
M24 x 3
M27 x 2
M30 x 2
M33 x 2
M36 x 3
1.3
1.3
7.1
6.5
12.7
11
20
18
30
-
45
-
60
-
80
-
100
-
100
140
190
240
-
3.5
7.9
7
13.9
12
22
19
33
-
48
-
65
-
90
-
110
-
-
-
-
-
NUTS (ZNT) SCREWS (ZNT / DEIDR)
-
3.9
8.2
7.7
14.5
12.9
21.6
20
34
-
50
-
64.5
-
-
-
108
-
-
-
-
-
1.2
2.6
5.2
5
8.7
8.1
13
12.5
17
-
25
-
30.5
-
41
-
47
-
40.1
49.9
-
-
Strenghth grade: 10 (R 80) Strength grade: 10,9 (R 100)

SECTION 1
ENGINE
TABLE OF CONTENTS
CHAPTER
1.1
1.2
1.3
1.4
1.5
SUBJECT PAGE
GENERALSPECIFICATIONS .............................................................................................. 1
SERIES "C" ENGINE DATA ................................................................................................. 3
DIAGRAMS OF SERIES "C" ENGINE ................................................................................. 6
MOUNTING OF ENGINE ON FRAME .................................................................................. 9
AFTERCOOLER FAN DRIVE SYSTEM................................................................................ 10
THROTTLELINKAGE........................................................................................................... 121.6

ENGINE
1 - 1D255
Technology
• In-line cylinders
• Water cooled
• 4 stroke
• Turbocharged
• After-cooled
• Direct injection
• Metric dimensions
• Air flow cooling
Length Width Height Weight
mm mm mm kg
Series C 1118 679 694 606
Engine components
• Metric specifications
Pipes connections and
plugs
• SAE standards
1.1 GENERAL SPECIFICATIONS
1. The Series C engine is a diesel for heavy duty
applications characterised by several design con-
cepts tending towards simplicity and a high com-
pactness.
2. The engine incorporates, in a single solution, all
the most important characteristics and advantages
of modern diesel technology.
3. The engine has been entirely designed with met-
ric dimensions. the only discrepancy with these
specifications involves the use of connections for
pipes and plugs with SAE standards. The specifi-
cations of accessories change depending upon
the Supplier. Technical publications list metric
values with the equivalent SAE values.

ENGINE
1 - 2 D255
2 1
Identification of the engine
Engine data plate
The engine data plate provides the identification data
and other important information about the engine.
Have the engine data here below available when con-
tacting a Cummins Authorised Repair Centre. The in-
formation data on the plate are compulsory when pro-
curing Spare Parts.
1. Serial number of the engine (E.S.N.)
2. Control Parts List (CPL)
Note – Do not change the engine data plate unless
authorised by Cummins Engine Company, Inc.
Nomenclature
Model of industrial engine
6 C T A 8.3
No. of cylinders
Series C
Turbocharged
After-cooled
Total displacement in litres
4. The engines are designated as follows:
The first digit indicates the number of cylinders,
the letter to follow indicates the series of the en-
gine, the remaining letters indicate the air intake
(T = turbocharged) and the last numbers indicate
the total displacement in litres.
5. The total displacement of the engine is 8 268 cm3
,
the bore is 114 mm and the stroke 135 mm.
The firing order is the same as for the other in-
line, 6 cylinder Cummins engines, 1-5-3-6-2-4.
Specifications of engine series
Total displacement 8 268 cm3
Bore 114 mm
Stroke 135 mm
Firing order 1-5-3-6-2-4

ENGINE
1 - 3D255
1.2 SERIES "C" ENGINE DATA
Generalities
Bore: ..........................................................................................................................................114 mm
Stroke: .......................................................................................................................................135 mm
Total displacement: .................................................................................................................8 268 cm3
Max. power rated speed ......................................................................................................... 2200 min-1
Net power at flywheel (SAE J1349) ............................................................................................ 177 kW
Maximum torque ........................................................................................... 114.6 daNm (at 1400 rpm)
Engine idle rated speed and various stalls:
Low idle ......................................................................................................................920 ± 100 rpm
Max. idle ................................................................................................................. 2150 ± 50 rpm
Equipment stall ........................................................................................................ 2080 ± 70 rpm
Torque converter stall................................................................................................ 1780 ± 100 rpm
Total stall (equipment plus torque converter) ............................................................. 1510 ± 100 rpm
Compression ratio .......................................................................................................................17.3 : 1
Firing order: ........................................................................................................................... 1-5-3-6-2-4
Valve clearance
Intake:................................................................................................................................. 0.30 mm
Exhaust: ............................................................................................................................. 0.61 mm
Engine rotation (seen from front side of engine): .................................................................... Clockwise
Intake ............................................................................................................................... Turbocharged
Engine weight (with standard accessories)
Dry:...............................................................................................................................603 ÷ 612 kg
Filled (with engine fluids) ............................................................................................... 635 ÷ 658 kg
Oil pressure
At low idle (minimum allowed) .................................................................................0.69 bar (69 kPa)
At nominal rpm (minimum allowed).............................................................................2 bar (207 kPa)
Pressure differential for oil filter by-pass valve opening .............................................. 1.68 bar (172 kPa)
Oil flow at rated speed (minus the flow through the pressure relief) ................................ 106.8 litres/min
Oil temperature at rated speed ............................................................................................ 99 to 126 °C
Oil temperature thermostat
Fully open (oil flowing through heat exchanger ........................................................................116 °C
Closed (part of the oil by-passes the heat exchanger).............................................................104 °C
Oil sump capacity (all engines) (high - low) .................................................................. 18.9 a 15.1 litres
Total capacity of system ......................................................................................................... 23.8 litres
Lubrication system

ENGINE
1 - 4 D255
Cooling system
Thermostats
Beginning of opening: .............................................................................................. From 81 to 83 °C
Fully open: ................................................................................................................................95 °C
Temperature of upper tank
Maximum allowed: ..................................................................................................................100 °C
Minimum recommended: ...........................................................................................................70 °C
Cap pressure with system at 99 °C (210 °F).................................................................0.42 bar (50 kPa)
Cap pressure with system at 104 °C (220 °F) ...............................................................1.3 bar (103 kPa)
Coolant pressure (Upper manifold) at rated speed of 2200 rpm...............................................................
............................................................................................................1.3 ÷ 2.7 bar (103 ÷ 276 kPa)
Coolant flow (thermostats fully open, at rated speed of 2200 rpm) .................................... 258 litres/min
Coolant capacity ..........................................................................................................................9 litres
Maximum restriction allowed at rated speed and nominal load (with dry air cleaner element)
..................................................................................................................................... 63.5 cm H2
O
Maximum restriction allowed at turbocharger outlet at rated speed and nominal load
...................................................................................................................................... 76.2 mm Hg
................................................................................................................................... 101.6 cm H2
O
Intake and exhaust
Fuel system
Maximum restriction at fuel pump inlet ................................................................................. 100 mm Hg
Minimum output pressure of fuel pump at rated speed
low delivery .............................................................................................................. 0.7 bar (83 kPa)
high delivery.......................................................................................................... 1.68 bar (172 kPa)
Restriction of fuel filter (maximum pressure drop through the filters) .......................... 0.345 bar (35 kPa)
Minimum pressure in pump duct at rated speed and high flow.................................... 1.37 bar (140 kPa)
Minimum pressure in pump duct at rated speed and low flow .......................................0.42 bar (48 kPa)
Restriction on fuel return (maximum).................................................................................... 518 mm Hg

ENGINE
1 - 5D255
Minimum capacity of recommended batteries
12 Volt system
18 °C Cold starting current ..................................................................................................... 1800 A
(Reserve capacity)*................................................................................................................ (640 A)
0 °C Cold starting current ....................................................................................................... 1280 A
24 Volt system**
18 °C Cold starting current ....................................................................................................... 900 A
0 °C Cold starting current ......................................................................................................... 640 A
* The quantity of plates for a given dimension of batteries determines its capacity. The reserve capacity
determines the length of the period during which a sustained starting is maintained.
** Per battery (two 12 Volt batteries in series). CCA specifications are based upon - 18 °C
Electrical system
Batteries (Specific gravity)
Specific gravity
at 27 °C
Charge status
1.260 - 1.280
1.230 - 1.250
1.200 - 1.220
1.170 - 1.190
1.110 - 1.130
100%
75%
50%
25%
Exhausted

ENGINE
1 - 6 D255
Fig. 1-8 View from injection pump side
1.3 DIAGRAMS OF SERIES "C"
ENGINE
The illustrations here below provide information on the
engine components, the location of filters, the drain-
ing points and the access locations for engine instru-
mentation and controls.
The illustrations and the configuration of the compo-
nents shown in these diagrams are of a general na-
ture. The locations of some components change de-
pending upon the application and the installation.
For the removal, testing, overhaul and installation of the engine,
please refer to the Workshop Manual Print Number 604.06.901.
Front lifting
bracket High pressure fuel pipes 1/4 " NPTF (air) M22 x 1.5 (air)
Fuel injection
pump
Engine front
mounting bracket
Oil draining plug
Rear lifting
bracket
Fuel/water
separator
Fuel pump
3/4 " x 16 " UNF point
for magnetic sensor
Oil filler
neck
Arrangement for sump
oil heating

ENGINE
1 - 7D255
Fig. 1-9 Rear view
Fig. 1-10 Front view
Cylinder
block
breather pipe
Turbocharger exhaust
outlet
Flywheel
housing
Centring bearing
Flex disc
mounting holes
Flywheel
Turbocharger
air intake
Belt tensioner
Water pump
Drive belt
Turbocharger air outlet
Coolant filter Fan pulley
Fuel pump drive cover
Alternator
Engine air intake
Vibration damper

ENGINE
1 - 8 D255
Fig. 1-11 View from turbocharger side
Turbocharger
exhaust outlet
Arrangement
for cab heater
Lube oil filter
Lube oil pressure
(before the filter)
Westgate
actuator
Arrangement
for coolant
heater
Lube oil temperature
thermostat
Lube oil pressure
(after the filter)
Turbocharger
oil draining
Water outlet
connection
Lube oil heat
exchanger
Turbocharger
air outlet
1/2" NPTF
(coolant)
Lube oil
temperature sensor
Coolant inlet
Arrangement
for coolant
temperature
sensor

ENGINE
1 - 9D255
1.4 MOUNTING OF ENGINE ON FRAME
Tightening torques
C1
. Self-locking nut M24 x 2 ................................ (108 daNm)
C2
. Screw TE M12 x 1.75....................................... (11 daNm)
C3
. Self-locking nut M16 x 1.5 ............................... (30 daNm)

ENGINE
1 - 10 D255
1.5 AFTERCOOLER FAN DRIVE SYSTEM
Gear
pump
8cc/turn
PT0speed
1,13enginespeed
38±2bar
with5L/min
Sequencevalve
Gearmotor
8cc/turn
16±2bar
with19L/min
Back
pressure
valve
Tank

ENGINE
1 - 11D255
6
5
3
4
2
1
7
Tank
1. Gear pump
2. Sequence valve
3. Gear engine
4. Counterpression valve
5. Radiator
6. Turbo
7. Support

ENGINE
1 - 12 D255
1.6 THROTTLE LINKAGE
Adjustment procedure
Connect adjustable link (1) to lever “A” using pin,
washer and split pin.
With throttle lever “B” in low idle position, position le-
ver “C” at the dimension indicated.
Adjust the fork complete with pin and stopper located
at one end of rod (1) until the securing holes corre-
sponding with the one of cam “D” is found.
Insert the pin and hook the stopper.
Hook spring “E” to the to pins.
Connect lever “C” to the injection pump using the ad-
justment of the forks located at the ends of rod (2)
and install the relevant pins, washers and split pins).

SECTION 2
TRANSMISSION
TABLE OF CONTENTS
CHAPTER TITLE PAGE
2.1 GENERAL DESCRIPTION ....................................................................................... 1
2.2 TROUBLESHOOTING .............................................................................................. 6
2.3 CONVERTER ........................................................................................................... 11
2.3.1 Removal ................................................................................................................... 13
2.3.2 Disassembly ............................................................................................................. 15
2.3.3 Checking parts.......................................................................................................... 15
2.3.4 Converter safety valve .............................................................................................. 19
2.4 TRANSMISSION ...................................................................................................... 20
2.4.1 Removal ................................................................................................................... 20
2.4.2 Disassembly transmission ........................................................................................ 25
2.4.3 Disassembly clutch .................................................................................................. 32
2.4.4 Assembly transmission ............................................................................................ 37
2.4.5 Lubrication oil pressure regulating valve.................................................................... 41
2.4.6 Exhaust valves ......................................................................................................... 42
2.4.7 Refitting transmission ............................................................................................... 42
2.5 TRANSMISSION DISTRIBUTOR ............................................................................. 43
2.5.1 Removal and disassembly ........................................................................................ 43
2.5.2 Checking parts.......................................................................................................... 47
2.6 CONTROL LEVER .................................................................................................... 51
2.6.1 Disassembly ............................................................................................................. 51
2.6.2 Operating diagram .................................................................................................... 52
2.6.3 Checking parts.......................................................................................................... 54
2.6.4 Safety deflector ........................................................................................................ 55
2.7 CONVERTER/TRANSMISSION HYDRAULIC PUMPS ............................................. 56
2.7.1 Disassembly and revision ......................................................................................... 57
2.8 TRANSMISSION OIL HEAT EXCHANGER .............................................................. 58
2.8.1 Cleaning and checking parts ..................................................................................... 58
2.9 DRIVE SHAFT/CONVERTER/TRANSMISSION ....................................................... 59
2.9.1 Dismantling and revision ........................................................................................... 59
2.9.2 Assembly ................................................................................................................. 59
2.10 OIL FILTER CONVERTER - TRANSMISSION ......................................................... 61
2.11 TESTING TRANSMISSION/CONVERTER ON THE VEHICLE ................................. 63
2.11.1 Testing gear selection with converter in stall............................................................. 63
2.11.2 Checking transmission-converter pressure .............................................................. 64
2.11.3 Checking clutch pressure ......................................................................................... 64
2.11.4 Lubricating oil pressure ............................................................................................. 65
2.11.5 Converter oil pressure ............................................................................................... 65
2.11.6 Transmission feed pressure check ........................................................................... 65
2.12 TECHNICAL DATA ................................................................................................... 66
2.13 TIGHTENING TORQUES ......................................................................................... 71
2.14 SPECIAL TOOLS ..................................................................................................... 74

TRANSMISSIOND255 2 - 1
CONVERTER/TRANSMISSION HYDRAULIC COM-
PONENTS
The circuit is fed by a three section pump (Pa, Pc,
Pr), respectively for transmission-converter supply,
converter supply, oil recovery from the gearbox,
flanged to the converter support box.
The oil reservoir is a part of the gearbox in which the
oil is separated from the oil in the gear housing and
the clutch.
The level of the oil in the gear housing and the clutch
is controlled by the recovery pump (Pr), which aspi-
rates it through a magnetic element filter and returns
it to the reservoir, together with the oil recovered from
the converter support box effected by dipping of the
coupling (VENTURI).
The oil in the gearbox reservoir is aspirated by the
pair of pumps (Pa and Pc).
The pump (Pa) maintains oil pressure for the gear
box clutch control.
The pump (Pc) sends oil to the converter to be added
to the supply coming from the control pump (Pa)
through the upper inlet of the gearbox oil pressure
regulating valve (7). With the gears in neutral, the
supply to the converter is reduced because part of
the supply of the pump (Pa) passes through the lower
outlet of the pressure regulating valve (7) directly to
the lubrication circuit.
The lubrication circuit is fed by the oil leaving the
converter which, with the gears engaged, corresponds
to the sum of the supply from pumps (Pc) and (Pa)
less minor leakage. The oil leaving the heat exchanger
(18) passes through the gearbox and flows into the
lubrication circuit of the drive shafts and the clutches.
The warning light (Temperature Trans.) on the Elec-
tronic Data Monitor (EDM) (1) in the cabin shows the
temperature of the oil before it enters the heat ex-
changer.
With the gears in neutral the transmission oil pres-
sure containing member (7) is moved downwards to
expose the lower outlet of the valve (7) thus reducing
the oil pressure as it enters the converter and in con-
sequence, the general pressure necessary for the
gradual engagement of the clutch.
The warning light (Pressure Trans.) on the EDM indi-
cates insufficient oil delivery pressure to the distribu-
tor. In this event check whether the light remains on
when the engine is running, if necessary stop the ve-
hicle immediately and carry out the checks described
in the relative paragraph.
The safety valve (21) regulates the pressure in the
lubrication circuit, opening when the pressure exceeds
4 bar with gears in neutral.
2.1 GENERAL DESCRIPTION
The oil is collected in the gear compartment, filtered
by the magnetic element filter (36) and aspirated by
the recovery pump (Pr) which returns it to the reser-
voir.
Gear shift is effected by means of the control lever
(8) which is fed by the pump (Pa). With the safety
valve (5) in the “UNLOCKED” position the oil coming
from the valve (3), after passing through the valve (6)
of the transmission distributor, feeds the control le-
ver. With the valve lever (5) in the “LOCKED” position
the oil, which previously fed the control lever is re-
leased.
In neutral and with the engine running at low revs the
valve (6) guarantees sufficient pressure for the con-
trol lever to work correctly.
When the gears are engaged the oil aspirated by the
pump (Pa) passes through the filter (2) which is fitted
with a renewable paper filter and a safety valve (20)
which protects it from blocking. The valve guaran-
tees the flow of oil by excluding the cartridge, totally
or partially, and preventing tearing.
With the control lever (8) in the neutral position the oil
coming from the pump (Pa) leaves the oil pressure
regulating valve (7) by both outlets: the upper is con-
nected to the converter, the lower to the lubrication
circuit of the gearbox. In this situation the oil, fed by
the pump (Pa) is at low pressure, because the valve
shutter (7) is subject only to the action of the spring.
Moving from neutral to the first reverse gear, the
pushrods (9 and 10) move from a central position to
the left forcing the distributor shaft (34) to move down-
wards and allowing the oil to move towards the 1st
speed clutch.
At the same time the distributor rod (28) moves down-
wards to the position shown and ensures the revers-
ing movement.
The ball valve (14) prevents pressure from being re-
leased through the forward gear conduit which is in
exhaust phase. At this point the regulating valve of
the reverse gear begins to operate as described be-
low.
The pressure of the oil, as already mentioned, is ini-
tially low and transfers to the valve (7), working with
the spring to determine the pressure which increases
with respect to the initial value set only by the spring.
Furthermore the pressure itself is created under the
piston of the regulating valve (29) through the throat
(15) causing first the compression of the external
spring with consequent pressure on the seal (30) and
a slow increase in the pressure under the valve (7).
The spring then compresses increasing the speed of
the closure of the seal (30) and consequently the pres-
sure on the reverse gear clutch pad.

TRANSMISSION2 - 2 D255
At the end of the cycle the washer will be completely
closed. The throat (15) regulates the time taken by
the piston (29) to complete its stroke while the throat
(12) allows small supplies to control the regulating
valve. A similar sequence occurs in the case of the
forward gear.
Moving the control lever to the second reverse gear
position the control lever send the pushrods (9 and
10) towards the centre. Pressure is removed from the
rod (34) and placed on the rod (32) which by moving
connects the feed line to the cylinder of the (empty)
gearbox. The pressure caused by the throat (27) is
reduced in the lower conduit of the gear regulating
valve and therefore the pistons (24) move downwards
due to the increased pressure acting on the upper
conduit which overcomes the spring (25).
This movement causes the outlet (26) to open mo-
mentarily lowering the pressure throughout the sup-
ply circuit. The gradual refilling of the clutch cylinder
in first gear causes an increase in the pressure which
acting on the lower piston gradually, together with the
action of the spring (25) moves both pistons upwards
bringing the feed pressure levels back to normal.
This sequence has caused a regulated increase of
the pressure on the selected gear (first). A similar
sequence occurs for the other gears.
The three valves therefore: regulate the increase in
pressure of the clutch control in order to ensure gradual
engagement and limit the maximum pressure values
of the transmission.
The purpose of the rapid exhaust valves (37), one for
each clutch, is to allow the direct release of the oil in
the gear housing when the control pressure reaches
zero, eliminating the centrifuging of the oil in the con-
trol housing, which tends to keep the clutch engaged
causing unnecessary strain.
The engagement of the gears and the direction in which
the vehicle moves, as already mentioned, is control-
led by the control lever.
In the neutral position (fig. 2-2) the oil from the safety
valve (5) enters the lever (8) by the joint d. In this
case since the inlets are not covered by the pistons
(44 and 54) the pressurised oil moves through the
control lever and through the distributor and engages
the second gear.
Pulling the control lever (43) backwards (fig. 2-1) the
piston (39) moves downwards allowing the oil from
the safety valve to reach the transmission distributor
engaging the selected gear (second reverse gear). At
the same time, the piston (39) connects the pressu-
rised oil coming from d with the chamber (41) under
the opposite piston (38), forward gear. The pressure
causes this piston to rise locking the control lever.
The throat (42) regulates the flow from the chamber
(41) to the exhaust (e). To release the lever (43) bring
it back to the neutral position, the piston (39) rises
due to the effect of the spring (40) interrupting the
supply to the chamber (41) allowing the piston (38) to
return to a neutral position, while the oil in the cham-
ber (41) is released through the throat.
Note – To engage the first forward gear or the first
reverse gear, two pistons are compressed at the same
time.

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