KOMATSU WA270-3 WHEEL LOADER Service Repair Manual SN：WA270H20051 and up

Shop Manual
VEBM340200
Wheel Loader Serial-no.
WA270-3 WA270H20051 and up
WA270PT-3 WA270H30051 and up
WA270-3
WA270PT-3
© 2001
All Rights Reserved
Printed in Europe 09-01

00-2
CONTENTS
00 SAFETY ............................................................................. 00-3
01 GENERAL ......................................................................... 01-1
10 STRUCTURE AND FUNCTION....................................... 10-1
20 TESTING AND ADJUSTING............................................ 20-1
30 DISASSEMBLY AND ASSEMBLY................................... 30-1
90 OTHERS ........................................................................... 90-1
No. of page

SAFETY Safety Notice
00-3
00 SAFETY
Safety Notice
= Important Safety Notice
Proper service and repair is extremely important for safe machine operation. Some of the described service
and repair techniques require the use of tools specially designed by Komatsu for the specific purpose.
To prevent injury to workers, the symbol = is used to mark safety precautions in this manual. The cautions
accompanying these symbols must always be followed carefully. If any dangerous situation arises or may
possibly arise, first consider safety, and take the necessary actions to deal with the situation.
= General Precautions
Mistakes in operation are extremely dangerous. Read the OPERATION AND MAINTENANCE MANUAL ca-
refully before operating the machine! Always follow the safety rules valid in your country carefully!
1. Before carrying out any greasing or repairs, read all the precautions given on the decals which are fixed to
the machine.
2. When carrying out any operation, always wear safety shoes and helmet. Do not wear loose work clothes,
or clothes with buttons missing.
l Always wear safety glasses when hitting parts with a hammer.
l Always wear safety glasses when grinding parts with a grinder, etc.
3. If welding repairs are needed, always have a trained, experienced welder carry out the work. When carrying
out welding work, always wear welding gloves, apron, glasses, cap and other clothes suited for welding
work.
4. When carrying out any operation with two or more workers, always agree on the operating procedure before
starting. Always inform your fellow workers before starting any step of the operation. Before starting work,
hang UNDER REPAIR signs on the controls in the operator's compartment.
5. Keep all tools in good condition and learn the correct way to use them.
6. Decide a place in the repair workshop to keep tools and removed parts. Always keep the tools and parts in
their correct places. Always keep the work area clean and make sure that there is no dirt or oil on the floor.
Never smoke while working. Smoke only in the areas provided for smoking.
Preparations for Work
7. Before adding oil or making any repairs, park the machine on hard, level ground, and block the wheels or
tracks to prevent the machine from moving.
8. Before starting work, lower blade, ripper, bucket or any other work equipment to the ground and install the
safety bar on the frame. If this is not possible, insert the safety pin or use blocks to prevent the work equip-
ment from falling. In addition, be sure to lock all the control levers and hang warning signs on them.
9. When disassembling or assembling, support the machine with blocks, jacks or stands before starting work..
10. Remove all mud and oil from the steps or other places used to get on and off the machine. Always use the
handrails, ladders or steps when getting on or off the machine. Never jump on or off the machine. If it is
impossible to use the handrails, ladders or steps, use a stand to provide safe footing.

Safety Notice SAFETY
00-4
Precautions during Work
11. When measuring hydraulic pressure, check that the measuring tool is correctly assembled before taking any
measurements.
12. When removing the oil filler cap, drain plug or hydraulic pressure measuring plugs, loosen them slowly to
prevent the oil from spurting out.
Before disconnecting or removing components of the oil, water or air circuits, first remove the pressure com-
pletely from the circuit.
13. The water and oil in the circuits are hot when the engine is stopped, so be careful not to get burned.
Wait for the oil and water to cool before carrying out any work on the oil or water circuits.
14. Before starting work, remove the leads from the battery. Always remove the lead from the negative (-) ter-
minal first.
15. When raising heavy components, use a hoist or crane.
Check that the wire rope, chains and hooks are free from damage.
Always use lifting equipment which has ample capacity.
Install the lifting equipment at the correct places. Use a hoist or crane and operate slowly to prevent the
component from hitting any other part.
Do not work with any part still raised by the hoist or crane.
16. When removing covers which are under internal pressure or under pressure from a spring, always leave
two bolts in position on opposite sides. Slowly release the pressure, then slowly loosen the bolts to remove.
17. When removing components, be careful not to break or damage the wiring. Damaged wiring may cause
electrical fires.
18. When removing piping, stop the fuel or oil from spilling out. If any fuel or oil drips onto the floor, wipe it up
immediately. Fuel or oil on the floor can cause you to slip, or can even start fires.
19. As a general rule, do not use gasoline to wash parts. In particular, use only the minimum of gasoline when
washing electrical parts. Do not smoke!
20. Be sure to assemble all parts again in their original places.
Replace any damaged parts with new parts.
l When installing hoses and wires, be sure that they will not be damaged by contact with other parts when
the machine is being operated.
21. When installing high pressure hoses, make sure that they are not twisted.
Damaged tubes are dangerous, so be extremely careful when installing tubes for high pressure circuits. Al-
so, check that connecting parts are correctly installed.
22. When aligning two holes, never insert your fingers or hand. Be careful not to get your fingers caught in a
hole.
23. When assembling or installing parts, always use the specified tightening torques. When installing protective
parts such as guards, or parts which vibrate violently or rotate at high speed, be particularly careful to check
that they are installed correctly.

SAFETY Foreword
00-5
Foreword
General
This shop manual has been prepared as an aid to improve the quality of repairs by giving the service personnel
an accurate understanding of the product and by showing them the correct way to perform repairs and make
judgements. Make sure you understand the contents of this manual and use it to full effect at every opportunity.
This shop manual mainly contains the necessary technical information for operations performed in a service
workshop. For ease of understanding, the manual is divided into the following chapters; these chapters are
further divided into the each main group of components:
Structure and Function
This section explains the structure and function of each component. It serves not only to give an understanding
of the structure, but also serves as reference material for troubleshooting.
Testing and Adjusting
This section explains checks to be made before and after performing repairs, as well as adjustments to be made
at completion of the checks and repairs. Troubleshooting charts correlating "Problems" to "Causes" are also in-
cluded in this section.
Disassembly and Assembly
This section explains the order to be followed when removing, installing, disassembling or assembling each com-
ponent, as well as precautions to be taken for these operations.
Maintenance Standard
This section gives the judgement standards when inspecting disassembled parts.
NOTE: The specifications contained in this shop manual are subject to change at any time and without any ad-
vance notice. Use the specifications given in the book with the latest date.

How to Read the Shop Manual SAFETY
00-6
How to Read the Shop Manual
Volumes
Shop manuals are issued as a guide to carrying out repairs.
Distribution and Updating
Any additions, amendments or other changes will be sent to Komatsu distributors.
Get the most up-to-date information before you start any work.
Filing Method
1. See the page number on the bottom of the page. File the pages in correct order.
2. Following examples show how to read the page number.
Example 1 (Chassis volume):
3. Additional pages: Additional pages are indicated by a hyphen (-) and number after the page number. File
as in the example.
Example:
Symbols
So that the shop manual can be of ample practical use, important safety and quality portions are marked with
the following symbols:
Symbol Item Remarks
Safety Special safety precautions are necessary when performing the work.
Caution Special technical precautions or other precautions for preserving stan-
dards are necessary when performing the work.
Weight Weight of parts of systems. Caution necessary when selecting hoisting
wire, or when working posture is important, etc.
Tightening
torque
Places that require special attention for the tightening torque during
assembly.
Coat Places to be coated with adhesives and libricants, etc.
Oil, water Places where oil, water or fuel must be added, and the capacity.
Drain Places where oil or water must be drained, and quantity to be drained.
10 - 3
Item number (10. Structure and Function)
Consecutive page number for each item
10-4
10-4-1
10-4-2
10-5
Added Pages
=
«
4
3
2
5
6

SAFETY Hoisting Instructions
00-7
Hoisting Instructions
= Heavy parts (25kg or more) must be lifted with a hoist, etc. In the DISASSEMBLY AND
ASSEMBLY section, every part weigthing 25 kg or more is indicated clearly with the
symbol:
If a part cannot be smoothly removed from the machine by hoisting, the following checks should be made:
1. Check for removal of all bolts fastening the part to the relative parts.
2. Check for existence of another part causing interference with the part to be removed.
Wire Ropes
1. Use adequate ropes depending on the weight of parts to be hoisted, refering to the table below:
« The allowable load in tons, is given by vertical tensible force.
« The allowable load value is estimated to be one-sixth or one-seventh of the breaking strength of the rope
used.
2. Sling wire ropes from the middle portion of the hook.
Slinging near the edge of the hook may cause the rope to slip off the hook during hoisting, and a serious
accident can result. Hooks have maximum strength at the middle portion.
Wire ropes:
(Standard "Z" or "S" twist ropes without galvanizing)
Rope diameter (mm) Allowable load (tons)
10 1.0
11.2 1.4
12.5 1.6
14 2.2
16 2.8
18 3.6
20 4.4
22.4 5.6
30 10.0
40 18.0
50 28.0
60 40.0
4
100% 88% 79% 71% 41%

Hoisting Instructions SAFETY
00-8
3. Do not sling a heavy load with one rope alone, but sling with two or more ropes symmetrically wound onto
the load.
= Slinging with one rope may cause turning of the load during hoisting, untwisting of the rope, or slipping of
the rope from its original winding position on the load, which can result in a dangerous accident.
4. Do not sling a heavy load with ropes forming a wide hanging angle from the hook.
When hoisting a load with two or more ropes, the force subjected to each rope will increase with the hanging
angles.
The table below shows the variation of allowable load (kg) when hoisting is made with two ropes, each of
which is allowed to sling up to 1000 kg vertically, at various hanging angles.
When two ropes sling a load vertically, up to 2000 kg of total weight can be suspended. This weight beco-
mes 1000 kg when two ropes make a 120° hanging angle. On the other hand, two ropes are subjected to
an excessive force as large as 4000 kg if they sling a 2000 kg load at a lifting angle of 150°.
300 600 900 1200 1500
1000
2000
2000
1900
1700
1400
1000
500
kg
Lifting angle (α)
Loadcapacity(kg)
α
Hebewinkel (°)
Gewicht(kg)

01-1
01 GENERAL
General overwiew WA270-3 .............................01-3
General overwiew WA270PT-3.........................01-4
Technical datas ................................................01-5
Weight table WA270-3 .....................................01-8
Weight table WA270PT-3 ................................01-9
List of lubricant and water .............................01-10
Maintenance schedule ....................................01-11
Outlines of service..........................................01-12
Torque list ....................................................01-16
General view of controls and gauges ............01-17
Emergency drive ............................................01-18

01-3
Dimensions, Operating Data
Buckets (capacities in
accordance with ISO 7546)
m³ 2.1 2.4
Specific density t/m³ 1.8 1.6
Bucket weight without teeth kg 950 1,050
Static tipping weight, straight kg 9,800 9,600
Stat. tipping weight, 40° articulated kg 8,600 8,500
Breakout force, hydraulic kN 107 101
Hydraulic lifting capacity, on ground kN 112 110
Operating weight kg 12,300 12,350
a Reach at full lift at 45° mm 950 1.000
b Dumping height at 45° mm 2,900 2,860
c Lift height, hinge pin mm 3,78 3,782
The 2.1/2.4 m³ standard buckets
shown in the table can also be
delivered with bolt-on cutting
edges, 2.2/2.5 m³.
d Height at bucket upper edge mm 5,075 5,075
e Digging depth, 0° mm 27 27
f Carry height, hinge pin mm 460 460
A Overall length mm 7,060 7,120 Special buckets:
3.4 m³ light material bucketB Wheelbase mm 2,900 2,900
C Bucket width mm 2.550 2.550
These values refer to
20,5 R25 tyres.
D Width over tyres mm 2,440 2,440
E Track width mm 1,880 1,880
F Ground clearance mm 460 460 Machine without additional
counterweightH Overall height mm 3,250 3,250
I:DTPBA270GBABMES.TBL
WA270-3
270-128
GENERAL DIMENSIONS, OPERATING DATA

01-4
WA270PT-3
Dimensions, Operating Data
Buckets (capacities in
accordance with ISO 7546)
m³ 2,0
Specific density t/m³ 1.75
Bucket weight without teeth kg 800
Static tipping weight, straight kg 8200
Stat. tipping weight, 40° articulated kg 7400
Breakout force, hydraulic kN 96
Hydraulic lifting capacity, on ground kN 99
Operating weight *) kg 12700
a Reach at full lift at 45° mm 1188
b Dumping height at 45° mm 2726
c Lift height, hinge pin mm 3838
d Height at bucket upper edge mm 5385
e Digging depth, 0° mm 126
f Carry height, hinge pin mm 332
A Overall length mm 7060
B Wheelbase mm 2900
C Bucket width mm 2500
These values refer to machines
with
20,5 R25 tyres.
D Width over tyres mm 2440
E Track width mm 1880
F Ground clearance mm 460 *) Machine without additional
counterweightH Overall height mm 3250
U:DTPBA270GB270PTABMES-PT.TBL
GENERAL DIMENSIONS, OPERATING DATA

01-5
SPECIFICATIONS
Engine
Flywheel horsepower (kW (PS)) 103,5 (141)
Maximum torque (Nm / rpm) 566 / 1,600
Axle,wheel
Main brake
PowertrainBrakes
GENERAL TECHNICAL DATAS
Machine model WA270-3 WA270PT-3
From Serial No. WA270H20051 WA270H30051
Model Komatsu S6D102E-1
Type 4-cycle, water-cooled, in-line,
6-cylinder, direct injection, with turbocharger
No. of cylinders – bore x stroke (mm) 6 – 102 x 120
Piston displacement (cm³) 5.900
Starting motor 24 V
Alternator 24 V
Battery 12 V x 2 / 105Ah
Rim pull 108 kN
Torque converter 3-element, 1-stage, single-phase (30H046)
Transmission Automatic 4-gear (Full-power-shift)
with kick-down
Reduction gear Spiral bevel gear
Differential Limited slip differential
Final drive Planetary gear single stage
Drive type Front-, rear-wheel drive
Tire 20.5R25
Turning circle Inside tire
5243 mm
Outside Bucket
5757 mm
Hydraulic operated brake with accumulator
Wet type disc brakes
Mechanical operated drum brakeParking brake up to serial-no. WA270H21037
from serial-no. WA270H21038 Mechanical operated disc brake

01-6
Set pressure for work equipment 3-spool type
(bar) 210
Cut-off pressure
(bar) 165
Set pressure for steering Orbit-roll valve type
(bar) 200
Boom cylinder Reciprocating piston
No. – bore x stroke (mm) 2 – 130 x 723
Bucket cylinder Reciprocating piston
Steering cylinder
Work equipment lever type Single lever
FORWARD 1. 7,2 km/h
2. 12,7 km/h
3. 27,2 km/h
Travel speed 4. 41,8 km/h
REVERSE 1. 7,2 km/h
2. 12,7 km/h
3. 27,2 km/h
Operating weight 11.900 kg
Delivery
Steering
system
Cylinder
Hydraulicsystem
Hydraulic pumps
Machine model WA270-3
Serial No. WA270H20051 and up
Type Articulated steering
Structure Hydrostatic
Work- and Steering-/Switch/Brake- and Servo pump
110 / 94 / 21
Controlvalve
(l/min.)
Work
equipmentTravelspeedWeights

01-7
Delivery
Steering
system
Cylinder
Hydraulicsystem
Machine model WA270PT-3
Serial No. WA270H30051 and up
Type Articulated steering
Structure Hydrostatic
Work hydraulic pump / Servo pump
175 / 23
Controlvalve
(l/min.)
Work
equipmentTravelspeedWeights
Hydraulic pumps
Set pressure for work equipment (bar) 210
Set pressure for steering (bar) 180
Boom cylinder Reciprocating piston
Bucket cylinder Reciprocating piston
Steering cylinder
Work equipment lever type Single lever
Two lever
Multi function lever
FORWARD 1. 7,2 km/h
2. 12,7 km/h
3. 27,2 km/h
Travel speed 4. 41,8 km/h
REVERSE 1. 7,2 km/h
2. 12,7 km/h
3. 27,2 km/h
Operating weight 12,700 kg

01-8
Engine
Radiator
Transmission
Center drive shaft
Front drive shaft
Rear drive shaft
Front axle
Rear axle
Axle pivot
Wheel (each)
Tire (each)
Orbit-roll valve
Priority valve
Steering cylinder (each)
Hydraulic tank
Main control valve
Machine model
From Serial No.
453
285
10.5
12.3
22.0
672
680
67.0
10.0
7.5
116.5
Machine model
From Serial No.
Boom cylinder (each)
Bucket cylinder
Engine hood
Front frame
Rear frame
Bucket link
Bellcrank
Boom (including bushing)
Bucket (with BOC)
Counterweight
Fuel tank
Battery (each)
Cab
Operator’s seat
Hydraulic pump
Unit: kg
WA270-3
WA270H20051
WA270-3
WEIGHT TABLE WA270-3
This weight table is a guide for use when transporting or handling components.
WA270H20051
85.0
990
707.5
46
257
854
910
1238
180
29.0
410
45
GENERAL WEIGHT TABLE

01-9
Engine
Radiator
Transmission
Center drive shaft
Front drive shaft
Rear drive shaft
Front axle
Rear axle
Axle pivot
Wheel (each)
Tire (each)
Orbit-roll valve
Priority valve
Steering cylinder (each)
Hydraulic tank
Main control valve
Machine model
From Serial No.
460
380
10.5
12.3
22.0
672
680
67.0
10.0
7.5
116.5
Machine model
From Serial No.
Boom cylinder (each)
Bucket cylinder
Engine hood
Front frame
Rear frame
Bucket link
Bellcrank
Boom
Bucket 2.0 m³
Counterweight
Fuel tank
Battery (each)
Cab
Operator’s seat
Quick coupler
Hydraulic pump
Unit: kg
WA270PT-3
WA270H30051
WA270PT-3
WEIGHT TABLE WA270PT-3
This weight table is a guide for use when transporting or handling components.
WA270H30051
85.0
67.5
85.0
990
707.5
30.0
46.1
532
910
1238
180
29.0
410
45
300
GENERAL WEIGHT TABLE

01-10
LUBRICANTSAND OPERATING EQUIPMENT
WA270-3
WA270PT-3
LUBRICANTS AND OPERATING EQUIPMENT
BI abbreviations *), specifications and filling quantities
Lubricants and
operating
equipment
BI abbreviation Quality class
Temperature
range
Viscosity
class
Filling
quantity in
litres
(approx.)
Engine EO engine oil
EO 1540 A
EO 1030 A
NRS
CCMC D4
or, if not available,
API CE or
API CF -4 ²)
-10° to 50°C
-25° to 20°C
-40° to 20°C
SAE 15W-40 ¹)
SAE 10W-30
SAE 05W-30
16
Transmission EO engine oil EO 10
CCMC D4
API CD
- SAE 10W 17
Axles with
multi-disc locking
differential
GO gearbox oil GO 90 LS API GL5+LS -
SAE 90 ¹)
SAE 85W-90
SAE 80W-90
2x25.5
Hydraulic system,
steering, brakes
HYD hydraulic oil HYD 0530 HVLP, HVLP D -35° to 50°C ISO VG 46 ¹)
120
or EO engine oil EO 10
CCMC D4
API CD
-35° to 40°C SAE 10W
or BIO-E-HYD
hydraulic oil
BIO-E-HYD 0530
HEES
(to VDMA fluid
technology)
-35° to 50°C
ISO VG 46
Cooling system
SP-C long-term
coolant with
anti-frost and rust
protection
SP-C
Anti-frost and rust
protection
56
Fuel tank Diesel fuel ³)
CFPP class B
CFPP class D
CFPP class E
CFPP class F
DIN-EN 590
up to 0°C
up to -10°C
up to -15°C
up to -20°C
185
Grease nipples,
central lubrication
Multi-purpose
grease on a lithium
basis
MPG-A KP2N-20 - NLGI 2
Air-conditioning
Coolant
Refrigerating
machine oil
NRS
NRS
R134a (CFC-free)
PAG (Polyalcohol glycol oil)
1000 g
150 cm ³
The specified filling capacities are approximate guidelines; test specifications are binding. The selection of the viscosity class
depends on the predominantly existing outside temperature. The temperature limits are to be regarded as guidelines which can be
exceeded up or down for a brief period.
*) Works filling **) Top-up quantity
²) If no engine oil of the API CE or API CF-4 specification is available, API CC or API CD-classified engine oil can be used
alternatively. The oil change intervals must be split in half in this case, however.
³) If the fuel sulphur content is between 0.5 and 1.0 %, the oil change interval must be 1/2 normal. With a sulphur content of more
than 1.0 %, the oil change interval must be 1/4 normal.
****) BI codes are the "standard lubricants" for construction machinery and vehicles of the Hauptverband der Deutschen
Bauindustrie e.V. (BI). The brochure "Regelschmierstoffe für Baumaschinen- und Fahrzeuge" (Standard Lubricants for Construction
Machinery and Vehicles" can be obtained from bookstores or Bauverlag GmbH, Wiesbaden and Berlin, under the ISBN no.
3-7625-3102-1.
GENERAL LUBRICATION CHART

01-11
CHECKLIST PRIOR TO STARTING UP
Checking coolant level, top up
Checking engine oil level, top up
Water separator, drain water and dirt deposits
Fuel filter, drain water
Checking drive belts
Checking fan
Checking electrical connections
Checking fuel level, top-up
Checking control panels
Checking parking brake
Checking service brake
Checking horn and reversing horn
Checking lighting for function, dirt and damage
Checking exhaust, exhaust gas colour and
exhaust noise
Checking measuring instruments
Checking steering wheel play and function
Checking rear-view mirror for alignment, dirt
and damage
INITIAL MAINTENANCE
AFTER THE FIRST 100 OPERATING HOURS
Transmission, change oil and filters
Service brake, change oil filter
Fuel tank, drain water
Fuel filter, change cartridges
Hydraulic system, change oil filter elements
Axles, oil change
EVERY 500 OPERATING HOURS
Fuel filter, change filter cartridges
Cooling system, check antifreeze in coolant
Transmission, change oil and oil filter
(at least every 12 months)
Engine, check valve clearance
Service brake, change oil filter
Drive belts, check tension pulley and fan bearing
Turbocharger, check mounts and play
Axles, oil change (at least every 12 months)
Lubrication:
1. Pivot steering (2 points)
2. Propeller shaft intermediate
bearing (1 point)
3. Universal joint on front cardan
shaft (5 points)
Cooling system, changing coolant and cleaning
interior (at least every 24 months)
Check vibration absorber
Check turbocharger and clean
Check three-phase generator and starter
Air-conditioning, change filter elements
Pressure tank, check gas pressure
Hydraulic system, oil change, change filter element
Check water pump
MAINTENANCEAS REQUIRED
Air filter: Installation and removal of filter elements,
cleaning filter elements, changing safety filter
Dust pre-extractor "turbo II": check, clean
Cleaning the radiator
Windscreen washer, checking fluid level, top up
Transmission, checking oil level, top
Replacing bucket teeth
Fuel tank, draining water and dirt deposits
Tyres, checking air pressure
Air-conditioning, cleaning condenser
Checking air-conditioning
Checking the coolant level
REGULAR MAINTENANCE
Hydraulic system, checking oil level, top up
Cleaning fresh-air filter elements
Lubrication: Rear axle bolts (2 points)
Engine, change oil and oil filter cartridge
Checking air induction system
Air-conditioning, check tension of the compressor
Van-belt
Batteries, check
Axles, check oil levels
Wheel nuts, check, retighten
Lubrication:
1. Bucket bolts (2 points)
2. Tilt rod bolts (2 points)
3. Tilt cylinder bolts (2 points)
4. Lift cylinder bolts (4 points)
5. Boom bolts (2 points)
6. Bucket tilt lever bolts(1point)
7. Steering cylinder bolts (4 points)
MAINTENANCE SCHEDULE
GENERAL MAINTENANCE CHART

01-12
OUTLINES OF SERVICE
GREASE:
• Grease is used to prevent wear and build-up of noise.
• Grease nipples not mentioned in the service section are for
overhaul purposes; for this reason, they do not need to be greased.
• If a part becomes sluggish after long use, lubricate with grease.
• Wipe off any old grease which is pressed out when lubricating.
Any sand or dirt in the grease causes considerable wear.
OIL:
• The oil in the engine and the hydraulic system is subject to extre-
me conditions (high temperatures, high pressure). The quality
decreases, therefore, as operation increases.
Always use oil types complying with the operation and temperature
specifications in the operation and maintenance manual. Always
observe prescribed oil change intervals.
• Special attention must be paid when storing, handling and, in
particular, topping up oil and grease to prevent these from becoming
soiled. The majority of functional faults are caused by unclean oil.
• Never mix different types or brands of oil.
• Always top up the prescribed oil quantities.
Functional disturbances can be caused by too much or too little
oil.
• If the oil in the work hydraulic system is not clear (milky), oil or air
is probably penetrating the circuit. In this case, contact you local
Komatsu dealer.
• If changing oil, change corresponding oil filter as well.
• We recommend having a regular oil analysis carried out by your
local Komatsu dealer in order to establish the condition of the
machine.
GENERAL MAINTENANCE GUIDLINE

01-13
FUEL:
• The fuel injection pump is a precision instrument. Fuel containing
water or dirt causes damage to the fuel injection pump.
• Take maximum care when storing fuel or refuelling to avoid any
soiling.
• Always use the fuel prescribed in the operation and maintenance
manual.
• Paraffin can precipitate from fuel at temperatures below -15 °C
and block filters and lines. Always use suitable fuel if working in
this temperature range.
• Always top up fuel at the end of each working day to prevent air
humidity precipitating and water forming in the fuel tank.
• If you want to drain dirt and water from the fuel tank, wait at least
ten minutes after filling so that the swirling foreign bodies can settle
again.
• Fuel system will have to be bled if it has been run dry or the filter
has been changed.
• Engine oil change periods will have to be reduced by half if fuel is
being used with a sulphur content of 0.5 to 1.0 % and reduced to
one quarter if fuel with a sulphur content of more than 1.0 % is
being used.
BIOLOGICALLY DEGRADABLE HYDRAULIC OILS AND GREASE:
• Biologically degradable hydraulic oils and grease - on a diester oil
basis - can be used in Komatsu machines. Please contact our
works dealers for the products approved by us and most suitable
for your requirements.
STORAGE OF OIL AND FUEL:
• Store oil and fuel indoors to prevent it being contaminated by water,
dirt or other foreign bodies.
• If storing for longer periods, lay the drum on its side so that the
filler opening is located at the side. This prevents moisture from
forming inside the drum.
• Drums being stored in the open must be covered with watertight
foil or other appropriate measures taken to protect them.
• Always use the principle "first in, first out" to prevent any loss in
quality if storing for longer periods of time, i.e. always use the
oldest oil or fuel first.

01-14
COOLANT:
• Always mix coolant according to specifications of machine-related
section of the maintenance manual.
• River water contains large quantities of calcium and other foreign
bodies. If using this type of water, scale collects in the engine and
the radiator and restricts heat exchange which can result in
overheating.
• Do not use water which is also not suitable as drinking water.
• When using anti-freeze, always observe the instructions in the
operating and maintenance manual.
• Our machines are supplied with original antifreeze from Komatsu.
This antifreeze prevents corrosion in the cooling system, among
other things, lubricates moving parts, raises the boiling point of
the coolant and must therefore also be used at hot working sites.
• Anti-freeze is inflammable and particular attention must therefore
be paid that it does not come into contact with naked flames.
• If the anti-freeze level is too low, it can cause overheating and
corrosion to the cooling system because of the air in the coolant.
• If the engine overheats and it is necessary to top up with coolant,
wait until the engine has cooled down before topping up.
FILTERS:
Filters are extremely important safety components. They prevent
foreign bodies from entering individual circuits and sections of
equipment and causing damage there.
• Change all filters regularly. Further details in this respect can be
found in the operating and maintenance manual. The filters will
have to be changed more frequently if working under extreme
conditions depending on the type of oil and fuel being used, e.g.
with a high sulphur content.
• Never attempt to clean cartridge filters and use them again.Always
replace these filters with new ones. If changing oil filters, check
whether there are any metal particles inside the old filter. If this is
the case, contact your local Komatsu dealer.
• Do not open the package with the replacement filters until
immediately before installing.
• Always use original filters from Komatsu.

01-15
DETAILS OF ELECTRICAL SYSTEM:
• Never remove or alter electrical components installed in the
machine.
• Never install any other electrical components other than those
approved by Komatsu.
• Pay attention that no water enters the electrical system if washing
the machine or working in the rain.
• Wet wiring or damaged insulation can result in insulation faults in
the electrical system and, consequently, functional faults in the
machine.
• If working close to the coast, clean the machinery carefully to
prevent any corrosion.
• A foreign source of power must never be connected to the fuses,
the starter switch or the battery relay.
• Maintenance of the electrical system consists of:
1. checking the tension of the belt for the three-phase generator
2. checking the belt of the three-phase generator for damage and
wear
3. checking the acid level in the battery.
WEARING PARTS:
• Wearing parts such as filter cartridge, air filter element, exhauster,
must be changed when carrying out regular maintenance work or
when the respective wear or dirt level limit has been reached.
• This work must be carried out regularly and correctly at the
prescribed intervals in order to ensure economical use of the
machine.
• Only use original KOMATSU spare parts
• Always quote the part number as listed in the spare parts catalogue
when ordering spare parts.

01-16
TORQUE LIST
• Unless otherwise specified, tighten the metric bolts and nuts
to the torque shown in the table.
• The tightening torque is determined by the width across flats
of the nut and bolt.
• If it is necessary to replace any nut or bolt, always use a
Komatsu genuine part of the same size as the part that
was replaced.
Tread diameter Width across
of the bolt (mm) flat (mm)
(a) (b)
Nm kpm
M 6 10 10 1
M 8 13 24 2,4
M 10 17 (15) 48 4,8
M 12 19 83 8,3
M 14 22 130 13
M 16 24 200 20
M 18 27 280 28
M 20 30 390 39
M 22 32 520 52
M 24 36 670 67
M 27 41 980 98
M 30 46 1330 133
M 33 50 1790 179
M 36 55 2310 231
M 39 60 2970 297
NOTE
When tightening panels or other parts having tightening fixtures made of plastic, be careful not to use
excessive tightening torque: doing so will damage the plastic parts.
Strength class
8.8
GENERAL TORQUE LIST

01-17
GENERAL VIEW
1 Main monitor
2 Horn switch
3 Hazard lamp switch
4 Directional lever
5 Speed control lever
7 Speed control lever stopper
8 Wiper switch
9 Emergency switch
10 Parking brake lever
11 Brake pedal
12 Steering column tilt lever
13 Accelerator pedal
14 Cigarette lighter
15 Lamp switch
16 Turn signal lever
17 Dimmer switch
18 Starting switch
19 Car radio
20 Kickdown switch
21 Lift arm and bucket control lever
22 Attachement cylinder control lever
23 Safety lock
24 Air-conditioner switch
25 Maintenance monitor
MAIN MONITOR
30 Turn signal pilot lamp
31 High beam pilot lamp
32 Centralized checking lamp
33 Engine pre-heating pilot lamp
34 Pilot lamp for front working lamp
35 Pilot lamp for rear working lamp
36 Transmission cut-off selector pilot lamp
37 Parking brake pilot lamp
38 Central warning lamp
39 Speedometer
40 Transmission shift indicator
41 ALS Electronic
44 Emergency steering operating monitor
MAINTENANCE MONITOR
50 Fuel gauge
51 Engine cooling water temperature gauge
52 Torque converter oil temperature gauge
57 Service meter
58 Air cleaner clogging warning pilot lamp
59 Battery-charging indicator lamp
60 Brake oil pressure warning pilot lamp
61 Engine oil pressure warning lamp
62 Transmission oil pressure warning pilot lamp
63 Engine water level warning lamp
GENERAL VIEW OF CONTROLS AND GAUGES
Main monitor
Maintenance monitor
GENERAL VIEW
GENERAL CONTROLS AND GAUGES

01-18
• The machine is fitted with a fully automatic trans-
mission. Gear changing and driving the machine is
no longer possible if there is a fault in the control
unit. An emergency drive can be switched on in
this case.
• The emergency drive is only designed to re-
move the machine from a danger zone or drive
to the next repair workshop on its own.
• Press the brake pedal when starting the engine
and make sure that no-one is in the danger
area.
• Switching on emergency drive in the event of a
fault in the control unit for automatic gear shift:
1. Stop the engine.
2. Apply parking brake and set drive direction lever to
neutral.
3. Push the emergency switch (2) lock (1) to the side,
hold in this position and press the switch. The emer-
gency drive is now switched on and the control
lamp in the switch lights up.
4. Press the brake pedal, start the engine and release
the parking brake.
5. Set the drive direction lever to forwards or reverse,
release brake pedal slowly and move off slowly.
NOTE:
• The machine will only drive in 2nd gear, irrespec-
tive of position of gear lever.
Turn off the emergency drive only when start-
ing switch is turned off!
From serial-no.
WA270H21038and up on WA270-3
WA270H30132and up on WA270PT-3
new transmission, without emergency steering
switch
NOTE:
The emergency switch might be located in an-
other place (above the parking brake lever).
From serial-no.
WA270H20051 up to H21038 on WA270-3
WA270H30051 up to H30132 on WA270PT-3
EMERGENCY DRIVE
GENERAL EMERGENCY DRIVE

STRUCTURE AND FUNCTION POWER TRAIN
10-1
10 STRUCTURE AND FUNCTION
Power train ...................................................... 10-3
Power train system .......................................... 10-4
Torque converter and gearbox piping ............... 10-6
Torque converter .............................................. 10-8
Principle of operation ..................................... 10-10
Powershift transmission................................. 10-11
Gear change control ...................................... 10-11
Construction of transmission 4WG-150.......... 10-13
Electro-hydraulic control valve ....................... 10-18
Inductive sender / Proximity switch ................ 10-19
Pressure check points for 4WG - 150 ........... 10-29
Solenoid expansions valve and
overlap valve ................................................. 10-29
Transmission hydraulic
system diagram ............................................. 10-31
Control valve with solenoid
expansions valve ........................................... 10-33
Thermostat valve ............................................ 10-38
Drive shaft ..................................................... 10-41
Front and rear axle......................................... 10-42
Differential ..................................................... 10-43
Wheel hub ..................................................... 10-46
Axle mountings ............................................... 10-51
Steering articulation joint ................................ 10-52
Assembly of the steering joint......................... 10-53
Steering system ............................................. 10-61
Steering column, orbit roll .............................. 10-62
Hydraulic steering system .............................. 10-63
Control sleeve ................................................ 10-68
Steering and working
hydraulic pump .............................................. 10-70
Steering orbit roll ........................................... 10-71
Steering valve block ...................................... 10-72
Steering damper ............................................ 10-74
Steering cylinder location ............................... 10-75
Steering cylinder ............................................ 10-76
Emergency steering pump ............................. 10-77
Brake system............................................... 10-102
Brake system circuit .................................... 10-103
Gear pump .................................................. 10-104
Pressure filter .............................................. 10-105
Brake pressure regulating valve .................. 10-106
Brake operation ........................................... 10-107
Brake valve.................................................. 10-108
Pressure switch ........................................... 10-111
Accumulator (Brake system) ....................... 10-112
Hydraulic accumulator ................................. 10-113
Main brakes ................................................. 10-114
Piston seals ................................................. 10-115
Hand brake (parking brake) ......................... 10-116
Work equipment hydraulic system ............... 10-132
Pilot servo system ....................................... 10-133
Oil cooler system ......................................... 10-134
Work equipment hydraulic
system diagram ........................................... 10-136
Steering and working
hydraulic pump ............................................ 10-138
Cut-off valve ................................................ 10-139
Main control valve........................................ 10-140
Shock and anticavitation valve..................... 10-142
Anticavitation valve ...................................... 10-143
Pressure control valve ................................. 10-144
Joystick, servo control valve ........................ 10-145
Lift cylinder .................................................. 10-147
Tilt cylinder................................................... 10-149
ALS-Control unit .......................................... 10-150
ALS hydraulic system .................................. 10-151
Hydraulic accumulator ................................. 10-154
Lifting frame................................................. 10-156
Bucket positioner and boom kick-out ........... 10-160
Machine monitor system .............................. 10-165
Pre-heater plug ............................................ 10-172
Electric wiring diagrams............................... 10-170
Air-conditioner ............................................. 10-301

10-2

10-3
POWER TRAIN
Outline:
• The motive force from engine (3) passes through
the engine flywheel and is transmitted to torque
converter (2), which is connected to the input shaft
of transmission (1).
• The transmission has six hydraulically actuated
clutches, and these provide four speed ranges for
FORWARD and three for REVERSE. The trans-
mission speed ranges are selected manually.
1. Transmission
2. Torque converter
3. Engine
4. Front axle
5. Front drive shaft
6. Center drive shaft
7. Rear drive shaft
8. Rear axle
• The motive force from the output shaft of
the transmission passes through center drive
shaft (6), front drive shaft (5) and rear drive
shaft (7), and is then transmitted to front
axle (4) and rear axle (8) to drive the wheels.

10-4
POWER TRAIN SYSTEM

10-5
1. Front tire
2. Final drive
3. Wet type multiple disc brake
4. Differential
5. Front axle
6. Front drive shaft
7. Flange bearing
8. Center drive shaft
9. Parking brake
10. Transmission
11. Rear drive shaft
12. Final drive
13. Wet type multiple disc brake
14. Differential
15. Rear axle
16. Rear tire
17. Engine
18. Torque converter
19. Steering and working hydraulic pump
20. Torque convertor and gear box pump
21. Switch pump
22. Brake and servo pump
23. Emergency steering pump
Outline:
• The motive force from engine (17) passes
through the flywheel and is transmitted to
torque converter (18).
The torque converter uses oil as a medium.
It converts the transmitted torque in accord-
ance with the change in the load, and trans-
mits the motive force to the input shaft of
the transmission.
In addition, the motive force of the engine
passes through the pump drive gear of the
torque converter, and is transmitted to steer-
ing and working hydraulic pump (19) and to
the switch pump (21), so that the pumps are
operated in this way.
• Transmission (10) operates the directional
spool and speed spool of the transmission
valve through the solenoid valves, and actu-
ates the six hydraulically actuated clutches
to select one of the four FORWARD or RE-
VERSE speeds.
The transmission speed range is selected
automatically.
• The output shaft of transmission (10) trans-
mits the power to the front and rear axles.
At the front, the power is transmitted to front
axle (5) through center drive shaft (8), flange
bearing (7), and front drive shaft (6).
At the rear, the power is transmitted to rear
axle (15) through rear drive shaft (11).
• The motive force transmitted to front axle
(5) and rear axle (15) has its speed reduced
by the bevel gear and pinion gear of differ-
entials (4) and (14), and is then transmitted
to the sun gear shaft through the differential
mechanism.
• The motive force of the sun gear is rduced
further by the planetary mechanism (2/
12)and is transmitted to the wheels through
the axle shaft.

STRUCTURE AND FUNKTION TORQUE CONVERTER
10-6
TORQUE CONVERTER AND GEARBOX PIPING
1. Power shift gearbox
2. Thermostat valve
3. Engine radiator
4. Transmission heat exchanger
in the main radiator
5. Transmission heat radiator
next to the main radiator
6. Sensor torque converter oil temperature
Up to SN WA270H20563

10-7
1. Power shift gearbox
2. Thermostat valve
3. Engine radiator
4. Transmission heat radiator
next to the main radiator
3
4
2
270_065a
1
5
Schematic sketch only!
TORQUE CONVERTER AND GEARBOX PIPING
SN WA270H20564 and up

10-8
TORQUE CONVERTER
1. Engine flywheel
2. Torque converter drive
bell-housing
3. Drive plate
4. Turbine
5. Torque converter housing
with impeller
6. Stator
7. Turbine output gear
8. Turbine output shaft
9. Hydraulic pump drive shaft
10. Transmission housing
11. Torque converter housing
Specifications :
Model: 30H046
Type: 3 part single
stage
Convertion grade: 2.9 : 1

10-9
Power flow:
• The torque converter is mounted between the en-
gine and the gear box. The power from the engine
flows through the flywheel and the torque converter
drive plate (3) into the torque converter housing
which contains the impeller (5). The rotating power
of the torque converter impeller is transmitted
through oil, to the turbine (4), the output shaft (8),
and the drive gear (7) and so to the gear box. The
hydraulic pumps are driven by the hydraulic pump
drive shaft (9).
Oil flow:
• Oil from the transmission pump flows through a
filter to the inlet port (A). Further through an oil
channel between the stator and impeller into the
impeller (5).
The impeller imparts the oil with centrifugal force,
the oil flows into the turbine (4) and transfers this
centrifugal force into rotating energy in the turbine.
The turbine rotates the output shaft (8) and, in turn,
the gearbox.
When leaving the turbine (4) the oil enters the stator
(6) and is diverted back into the torque converter
impeller. Some of the oil is allowed to flow through
a channel and out of the torque converter (B) to
the oil cooler.

10-10
TORQUE CONVERTER
PRINCIPLE OF OPERATION
Impeller
Turbine
From
engine
To the
gear-box
Condition on taking
up the drive
Drive engaged
Middle position
Machine is not moving
Operation principle of a hydrodynamic
torque converter:
• The torque converter operates using the so called
Trilok system. That means, by higher turbine rpm it
operates with the advantages characteristics of a
fluid flywheel. The torque converter is designed to
fit the engine power so that there is an optimal
power transfer.
• The torque converter consists of three main parts:
Impeller, turbine and stator (reaction part).
• The three parts have ring formed shovels and are
fitted together so that the oil flows through them in
the order: impeller, turbine, stator. The transmis-
sion oil pump continually pumps oil through the
torque converter when the engine is running. This
allows the torque converter to operate effectively
and multiply the engine torque. Heat generated
during this process is removed by the oil. The oil is
thrown out of the impeller and passes into the tur-
bine. The turbine is driven by the force of the oil
entering it, the oil changes its direction of flow on
entering the turbine. Depending on the degree of
direction change, the turbine transfers more or less
torque to the gear-box input shaft. After leaving the
turbine the oil enters the stator. This causes the oil
to again change direction so that it can re enter the
impeller.
• The oil re-entering the turbine causes a re-
action torque. The relationship, turbine torque
/ impeller torque is referred to as the torque
conversion. This increases as the rpm dif-
ference between the two (impeller and tur-
bine) increases. As the output rpm increases
so the transferred torque decreases. The
torque variation takes place automatically.
When the turbine rpm reaches about 80%
of the impeller rpm then the torque conver-
sion is 1 : 0 ; that is the turbine torque is the
same as the impeller torque.
The torque converter is now working like a
fluid flywheel.
T
P
= Impeller torque
T
T
= Turbine torque
T
R
= Stator torque
Stator

STRUCTURE AND FUNCTION TRANSMISSION
10-11
POWERSHIFT TRANSMISSION
• The full powershift gearbox is of the layshaft type
construction. The gear change is hydraulically op-
erated through multi-disc clutch packs. See fig 1.
All gears are in permanent mesh and run on roller
bearings. The gears, bearings and clutch packs
are lubricated with cooled oil. The four speed re-
versing gearbox has six clutch packs. The required
gear is operated through a clutch pack. An axial
movable piston, under hydraulic pressure, com-
presses the clutch pack and so engages the se-
lected gear.
• Pressure springs ensure that the piston is returned
to the neutral position when the hydraulic pressure
is released, so releasing the clutch pack. The gear-
box and clutch pack construction is given in detail
in figs. 1,6 and 7.
TRANSMISSION CONTROL
Gear change control see oil flow scheme fig. 7 and 8.
• Oil for the torque convertor, gearbox lubrication and
the gear change clutch packs is supplied form a
pump. The pump is mounted in the gearbox and is
driven directly from the engine.
• Pump capacity : Q = 52 l/min, at 2000 engine rpm.
• The pump takes oil from the transmission sump
through a course filter. The oil is then delivered
under pressure, through an externally mounted fine
filter, to the max. pressure control valve (SDV). Oil
under pressure is now available in the pressure
governing valve (DSV), and at the solenoid valves
1, 2, 3, 4 and 5 for the clutch packs. The pressure
governing valve is responsible for the pressure build
up in the clutch packs after each gear change.
During a gear change the pressure drops
off and rises again, to complete the gear
change, to 16+2
bar.
• The signal for the gear change comes from
the fully automatic EST 25.
• The solenoid valve (M6) (expansion valve)
is always energised and is de-energised for
a programmed time during gear changing.
• At the start of a gear change the expansion
valve is kept energised for a short pro-
grammed time. During this time the clutch
pack can be filled at high pressure. After the
clutch pack is filled the expansion valve is
de energised and the clutch pack picks up
the drive with modulated pressure. When
the drive is taken up the expansion valve is
energised again and the system pressure
holds the selected gear until a further gear
change is made.
• The bleeding valve (EV) is provided to keep
the area behind the pressure governing
valve full with oil.
• When changing down from 2nd to 1st gear
a hydraulic overlap is allowed so that the
2nd clutch pack is still engaged even though
1st gear is being engaged. The spring accu-
mulator in the forward clutch pack (KV) cir-
cuit holds the forward clutch pack with 10
bar hydraulic pressure so that traction is
maintained during gear changing.
• The servo pressure for moving the gear
change valves is reduced to 10 bar with the
use of a restrictor. The servo pressure is
controlled with the solenoid valves M1, M2,
M3, M4 and M5.
Pressure curve during gear change:
P. Pressure in bar
t. Time in sec.
p1. Modulation begin
p2. Modulation end
ps. System pressure - modulated

10-12
• The pressure control valve (SDV) limits the max.
pressure, the excess oil is sent to the torque con-
verter and the lubrication system.
• The oil flow to the torque converter is protected
from high pressure with a safety valve. (Opening
pressure 8.5 bar).
• The oil in the torque converter is used to transmit
the drive torque using the hydrodynamic principle.
(See chapter Torque converter).
• To prevent cavitation the torque converter must be
kept full with oil. This is achieved by using a torque
converter pressure holding valve in the outlet line
from the torque converter.
• The oil coming out of the torque converter is sent
through a heat exchanger. (Oil-water or oil-air).
• A thermostat is fitted in the heat exchanger circuit
to enable a quick oil warm-up time.
• The oil flows from the heat exchanger into the lu-
brication circuit of the gearbox so that this circuit is
supplied with cooled oil for lubrication.
• The main oil control valve contains 5 solenoid
valves. (See fig. 8). Operation of the valves and the
gear change can be seen in figs. 6 and 7. There is
a different solenoid combination for each gear.
• The electric switching of the gears enables a light
and exact gear change. The cables allow for sim-
pler machine construction.
PTO
• There is a PTO to enable the main hydraulic
pumps to be driven when the engine is run-
ning.
Emergency steering pump
• Mounting of an emergency steering pump is
provided. (Axial piston pump, capacity :
16cm3
/ U).
Speedo drive
An electronic system is used.
• The speedometer signal is taken from the
gearbox output shaft.

10-13
CONSTRUCTION OF POWERSHIFT TRANSMISSION 4WG-150
FIG. 1
1. Drive flange
2. Torque converter
3. Forward clutch pack (KV)
4. 1st clutch pack (K1)
5. Torque converter and
gearbox pump
6. 1st. PTO
7. 2nd clutch pack (K2)
8. 3rd clutch pack (K3)
9. Parking brake (Drum brake)
10. Output front axle
11. Speedo drive (mechanical)
12. Oil sump
13. Output rear axle
14. 4th clutch pack
15. Reveres clutch pack (KR)
16. Idler gear
17. KV-gear
18. K4-gear

10-14
TO FIG. 1
1. Drive gear from turbine shaft
3. Forward clutch pack (KV)
4. 1st clutch pack (K1)
7. 2nd clutch pack (K2)
8. 3rd clutch pack (K3)
14. 4th clutch pack (K4)
15. Reveres clutch pack (KR)
16. Idler gear
17. Gear drive for emergency steering pump
18. Output drive gear
A. Drive gear turbine shaft
B. Drive gear clutch KR
C. Drive gear clutch K4
D. Idler gear between KV and K4
E. Drive gear clutch KV
FRONT VIEW (TO CONVERTER)
• Turbine shaft to clutch drive
Idler gear
Turbine
drive

10-15
CONSTRUCTION OF TRANSMISSION 4WG - 150 / FRONT VIEW
FIG. 2
1. Drive flange - direct to the flywheel
2. Transport plate
3. Electro - hydraulic control valve
4. Turbine rpm inductive sender (in put rpm)
5. Connection to the heat exchanger
6. Oil pick up pipe
7. Oil drain screw M22x 1.5
8. Oil level mark
9. Oil filler pipe and dip stick
10. Out put rpm inductive sender
11. Counter shaft

10-16
CONSTRUCTION OF TRANSMISSION 4WG-150 / SIDE VIEW
FIG. 3
Construction of the main control valve see fig. 5
1. Drive flange
2. Torque converter
3. Bell housing
4. Connection to heat exchanger
6. Output to front axle with drum brake
7. Name plate
8. Oil drain screw M22x1.5
9. Output to rear axle
10. Oil filler pipe and dip stick
11. Turbine rpm inductive sender
12. Check point torque converter output pres-
sure

10-17
CONSTRUCTION OF TRANSMISSION 4WG-150 / REAR VEIW
FIG. 4
1. Pipe to over lap valve 2nd gear clutch pack
2. Breather
Filter separate mounting:
3. Connection from filter
4. Connection to filter
5. PTO
Pipe connections from channel plate
to the clutch packs:
6. 1st (K1)
7. Forwards (KV)
8. Reverse (KR)
9. 2nd (K2)
10. 3rd (K3)
11. 4th (K4)
12. Output to front axle with drum brake
S. Oil pick up pipe M33x2
D. Pressure connection M22x1.5
14. Connection to overlap valve
15. Check valve for the overlap valve

10-18
CONSTRUCTION OF TRANSMISSION 4WG-150
ELECTRO-HYDRAULIC CONTROL VALVE
FIG. 5
1. Pipe from over lap valve to 2nd clutch pack (K2)
2. Electro - hydraulic control valve
3. Over lap valve bleed pipe
4. Solenoid and expansions valve
5. Overlap valve
6. Pressure pipes from accumulator to forwards clutch pack (KV)
7. Accumulator
8. Pressure test point, system pressure
9. Accumulator pressure pipes (10 bar)
10. Connection 2nd clutch pack (K2)
11. Connection from overlap valve
12. Check valve for the overlap valve

10-19
INDUCTIVE SENDER
Gear
Toeque 30 Nm
(Accalerator)
Proximity switch
Mounting plate
LED
• The inductive sender is used to pick-up the engine
RPM to control the gear change down cut-off. It is
mounted on the gearbox, easy to reach and has no
mechanical wear.
The sender is connected to the electronic control
unit with two wires.
For operation of the speed dependant automatic
gear change, an inductive sender is fitted to pick
up the out-put RPM, it also operates the electronic
tacho.
Adjustment:
The adjustment is with shims. The gap is 0.5 + 0.5mm
PROXIMITY SWITCH:
• To recognise loading of the injection pump.
• A proximity switch is fitted to the injection pump
control to pick up the loading of the injection pump,
(RPM). At approximately 1600 RPM a plus signal is
sent to the input plug ED9 of the electronic control
unit.
Adjustment:
• Fit a rev. counter to the engine. Move the proximity
switch in its long mounting hole so that the LED
lights up at an injection pump setting of 1600 RPM,
or a voltage of 24v is measured at connector 2 on
the proximity switch. The gap between the proxim-
ity switch and the injection pump control rod
is 1.5 - 3.0mm.
High idle Low idle

10-20
PRESSURE CHECK POINTS 4WG-150
SOLENOID EXPANSION VALVEAND OVERLAP VALVE
FIG. 6
Pressure and temp. check points:
51. Torque converter inlet M10x1
(Opening press. 8.5 bar)
63. Torque converter outlet M14x1.5
(opening pressure 5 bar)
Volume check points:
15. Connection to heat exchanger M26x1.5
16. Connection from heat exchanger M26x1.5
Inductive sender:
1. Turbine rpm M18x1.5
2. Drive rpm M18x1.5
Solenoid Valves:
M6.Solenoid expansion valve
M7.Overlap valve
E. Breather

10-21
ELECTRO - HYDRAULIC CONTROL VALVE - DETAIL ‘ X ‘
¡ = M6 Solenoid not energised for programmed time during gear
change
¡ = M7 Solenoid energised for programmed time during gear change
from 2nd to 1st.
63. Torque converter outlet M14x1.5
(Temp. 100°C, short time 120°C
and opening pressure 5 bar)
65. System pressure 16+2
bar M10x1
66. Pressure reducing valve 10 bar M10x1
Volume check points:
15. Connection to heat exchanger M26x1.5
16. Connection from heat exchanger M26x1.5
l Solenoid energized
FORWARD REVERSE NEUTRAL
GEAR 1 2 3 1 2
M1 l l
M2 l l
M3 l l
M4 l l l l l
M5 l
M6 ¡ ¡ ¡ ¡ ¡ ¡
M7 ¡
Clutch KV KV K4 KR KR K3
Clutch K1 K2 K2 K1 K2
Pressure and temp. check points:
51. Torque converter inlet M10x1
(Opening press. 8.5 bar)
53. Forwards clutch pack KV M10x1
55. Reverse Clutch pack KR M10x1
56. Clutch pack K1 M10x1
Scheme code ‘G’ - 4-speed version: Scheme code ‘G’ - 3-speed version (20 km/h):
l Solenoid energized
FORWARD REVERSE NEUTRAL
GEAR 1 2 3 4 1 2 3
M1 l l l
M2 l l
M3 l l l
M4 l l l l
M5 l
M6 ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡
M7 ¡
Clutch KV KV KV K4 KR KR KR K3
Clutch K1 K2 K3 K3 K1 K2 K3

10-22

10-23
TRANSMISSION HYDRAULIC SYSTEM DIAGRAM
Referalsotofig.6and7
17.Thermostatvalve
18.Heatchanger
Press.drop≤1bar
19.Filter
Filtrationµm:ß30
≥20
ß10
≥1.5
Filtrationareacm2
:2450
20.Oilpump
p=16+2
bar
Qp
=52l/min-1
at2000rpm
21.Checkvalves0,15bar
22.Springaccumulator
23.Checkvalve0,5bar
24.Dashboardtorqueconverter
outputtemerature
25.Dashboardpressuregauge
26.Lubrication
27.Sump
28.Torqueconverter
SDV.Controlpressurevalve16+2
bar
RDV.Reducingvalve10bar
WSV.Torqueconvertersafetyvalve8.5bar
WDV.Torqueconverterpressureholdingvalve
DSV.Pressurecontrolvalve
ÜSV.Overlapvalve
SPV.Expansionvalve
EV.Breathervalve
Clutchpressure
Reducedpressure
Modulatedpressure
Torqueconverterinputpressure
Torqueconverteroutputpressure
Lubrication
Returntosump
10-23

10-25
CONTROL VALVE WITH SOLENOID EXPANSION VALVE
AND OVER LAP VALVE
FIG. 8
1. Expansions valve solenoid
2. Over lap valve
3. Bleed valve
4. Over lap valve solenoid
5. Expansions valve
6. Switch valve 3
7. Switch valve 5
8. Switch valve 1
9. Switch valve 2
10. Pressure control valve
11. Reducing valve 10 bar
12. Switch valve 4
13. Control pressure valve 16+2
bar

10-26
THERMOSTAT VALVE
• The thermostat valve is fitted to allow a quick warm
up of the gearbox and torque converter tempera-
ture. It is mounted between the gearbox and the
heat exchanger.
Opening temperature: 87 ± 2 °C
Completely open: 102 °C
A. Connection to the gearbox
B. Connection to the heat exchanger
C. Connection to the return line from the heat ex-
changer and to the gear box oil sump
1. End screw
2. seal ring
3. Pin
4. Spring plate
5. Wax element
6. Pressure spring
7. Thermostat housing
8. Valve body
270_063a
7 9
7
9
SN WA270H20564 and up
Up to SN WA270H20563

10-27
STRUCTURE AND FUNCTION REVERSE TRANSMISSION 4WG-160
1. Clutch shaft "KR"
2. Power take-off; coaxial; engine-dependent
3. Clutch shaft "KV"
4. Clutch shaft "K2"
6. Output flange - rear
7. Abtriebsflansch - wandlerseitig
8. Output shaft
9. Transmission pump
10. Input flange - input through universal shaft
11. Converter
12. IInductive transmitter for engine speed
14. Converter relief valve
GEAR PATTERN
ABB. 1
LAYOUT TRANSMISSION 4WG-160

10-28
STRUCTURE AND FUNCTION REVERSE TRANSMISSION 4WG-160
INSTALLATION VIEW 4WG-160 / FRONT VIEW
1. Lifting lugs
2. Input flange - input through universal shaft
3. Transmission suspension threads M20
4. Output flange - converter side
5. Oil drain plug with magnetic insert M38x1,5
6. Model identification plate
7. Atachment possibility for oil level tube with oil dip
stick (coverter side)
8. Attachment possibility for emergency steering pump
ABB. 2

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KOMATSU WA270-3 WHEEL LOADER Service Repair Manual SN：WA270H20051 and up

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KOMATSU WA270-3 WHEEL LOADER Service Repair Manual SN：WA270H20051 and up