Summer Training Report Maruti Cars Transmission

1. A
SUMMER TRAINING REPORT
Submitted By: Asha Kumari
Submitted to:
Mr. Laxman Kumar Pandey
Department of
Mechanical & Automation Engineering
Amity School of Engineering
& Technology
Amity University Rajasthan
1

2. 2014
ACKNOWLEGMENT
It has come out to be a great pleasure and experience for me to be a summer trainee
at Vipul Motors (MSIL).I wish to express my indebtedness to those who guided and
helped me, Mr. Laxman Kumar Pandey, Mr. Amit Sharma, Naresh Dutta (General
Manager, Vipul Motors) & Mr.ChandraShekhar. This would not have been
successful without their help and precious suggestions. Finally I want to thank all my
colleagues who made the experience good at the training.
Asha Kumari
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3. TABLE OF CONTENTS
1. Introduction……………………………………………….
…………….............5
2. Transmission
Systems.........................................................................................7
3. Manual Transmission
System.............................................................................9
3.1
Advantage.....................................................................................................10
3.2
Clutch............................................................................................................10
3.3 Gear Box in Front Wheel Drive or
Transaxle...............................................12
3.4Gear Box in Rear Wheel
Drive.......................................................................13
3.5 Gear Shift
Lever.............................................................................................14
3.6 Shift
Fork........................................................................................................15
3.7 Gear Shift Control Lever and Cable
Components..........................................16
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4. 3.8 Gear Shift and Select Shaft Assembly
components........................................17
3.9 Gear Shift
mechanism.....................................................................................17
3.10. Input Shaft And Counter Shaft Assembly
components................................20
3.11. Gear
Box.......................................................................................................20
3.12 The Drive
Shaft..............................................................................................30
3.13 Differential Gear
Box.....................................................................................31
3.14 Transfer Gear
Box..........................................................................................34
3.15 Defects in Gear
Box.......................................................................................34
3.16 Manual Transmission Symptom
Diagnosis....................................................35
4. Automatic
Transmission..........................................................................................36
4.1
Description.......................................................................................................3
7
4.2 Functions of Components..........................................................................38
4.3 Automatic Transmission Modes.................................................................39
4.4 Electronic Control....................................................................................39
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5. 5. Automatic Manual Transmission………………………………………………..
…48
5.1 Direct Shift Transmission…………………………………………………...
…48
5.2 Electro Hydraulic Manual
Transmission………………………………………49
5.3
Advantages…………………………………………………………………….50
5.4
Disadvantages………………………………………………………………….50
6. Continuously Variable
Transmission………………………………………………51
6.1 Advantage of the
CVT…………………………………………………………52
6.2 Disadvantage of the
CVT……………………………………………………...52
7. Advance
Features…………………………………………………………………..53
7.1 Detent Pin
Technology………………………………………………………...53
7.2 Diagonal Shift
Assistance……………………………………………………...54
7.3 Reverse Shift
Prevention……………………………………………………….54
7.4 Reverse Gear
Actuation………………………………………………………..55
8. Case
Study……………………………………………………………………........56
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6. 9.
Conclusion………………………………………………………………………….
58
10.
Reference………………………………………………………………………….5
9
1. INTRODUCTION
Before the steam engine was invented, all of the physically demanding jobs like
construction, agriculture, shipping, and even traveling, were done by strong animals
or human beings themselves. The invention of the steam engine prompted the
Industrial Revolution, at which time human beings started using automated machines
to reduce human work load and increase job efficiency.
Even though it solves the dimension and slow start issues of the steam engine, the
internal combustion engine generates another serious problem. When the piston is
running at high speed, the pressure needed is also high, which violates the physics
rule of motion. Running an engine at high speed with high pressure is not efficient,
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7. and also decreases the engine life. To solve this problem, the transmission system
was invented.
To transfer engine power efficiently, the gear ratio between the engine and wheels
plays a very important role. When we use a screwdriver, the portion we hold has a
larger diameter, while the portion contacting with the screw has smaller diameter.
This design makes users use less force to unscrew a screw while applying force on a
larger diameter portion of the screw driver. Therefore, attaching a smaller gear to the
engine side and connecting it to a larger gear to deliver power to wheels helps
overcome friction when moving a static vehicle.
The figure 2 shows that the large gear of the wheels needs less force to drive it.
However, it also shows that when the engine gear turns one circle, the wheel gear
only turns about one half. The car won’t run as fast as possible.
Consider the following situation from Figure 3: the wheel gear has a smaller size,
which needs more force to move it while the car is static.
It won’t even be possible to move the car if the engine power is not large enough.
However, when the engine gear turns 1 cycle, the wheel gear may turn 2, which
makes the car run faster.
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8. Based on the physics rule of motion, after the object starts moving, the driving force
needed becomes smaller. Therefore, if the car can run on the large gear condition
(Figure 2) when starting, but change to a small gear (Figure 3) when moving, that is,
applying a large force when starting, but a small force when moving, this will makes
the power transmission much more efficient.
2. TRANSMISSION SYSTEMS
The most common transmission systems used in Maruti cars the automotive industry
are:
· Manual transmission,
· Automatic transmission,
· Semi-automatic transmission,
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9. · Continuously-variable transmission (C.V.T.).
Manual Transmission
The first transmission invented was the manual transmission system. The driver
needs to disengage the clutch to disconnect the power from the engine first, select the
target gear, and engage the clutch again to perform the gear change. This will
challenge a new driver. It always takes time for a new driver to get used to this skill.
Automatic Transmission
An automatic transmission uses a fluid-coupling torque converter to replace the
clutch to avoid engaging/disengaging clutch during gear change. A completed gear
set, called planetary gears, is used to perform gear ratio change instead of selecting
gear manually. A driver no longer needs to worry about gear selection during driving.
It makes driving a car much easier, especially for a disabled or new driver. However,
the indirect gear contact of the torque converter causes power loss during power
transmission, and the complicated planetary gear structure makes the transmission
heavy and easily broken.
Semi-Automatic Transmission
A semi-automatic transmission tries to combine the advantages of the manual and
automatic transmission systems, but avoid their disadvantages. However, the
complicated design of the semi-automatic transmission is still under development,
and the price is not cheap. It is only used for some luxury or sports cars currently.
Continuously Variable Transmission (C.V.T.)
The Continuously Variable Transmission (C.V.T.) is a transmission in which the
ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a
vehicle or other machine, can be varied continuously within a given range, providing
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10. an infinite number of possible ratios. The other mechanical transmissions described
above only allow a few different gear ratios to be selected, but this type of
transmission essentially has an infinite number of ratios available within a finite
range. It provides even better fuel economy if the engine is constantly made run at a
single speed. This transmission is capable of a better user experience, without the rise
and fall in speed of an engine, and the jerk felt when changing gears. Maruti offers
C.V.T. transmission in” KIZASHI”
3. MANUAL TRANSMISSION SYSTEM
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11. Manual transmissions also referred as stick shift transmission or just ‘stick', 'straight
drive', or standard transmission because you need to use the transmission stick every
time you change the gears. To perform the gear shift, the transmission system must
first be disengaged from the engine. After the target gear is selected, the transmission
and engine are engaged with each other again to perform the power transmission.
Manual transmissions are characterized by gear ratios that are selectable by locking
selected gear pairs to the output shaft inside the transmission. The transmission
provides five forward speeds and one reverse speed by means of three synchromesh
devices and three shafts-input shaft, countershaft and reverse gear shaft. All forward
gears are in constant mesh, and reverse uses a sliding idler gear arrangement. The
low speed synchronizer sleeve & hub is mounted on countershaft and engaged with
countershaft 1st gear or 2nd gear, while the high speed synchronizer sleeve & hub is
done on input shaft and engaged with input shaft 3rd gear or 4th gear. The 5th speed
synchronizer sleeve & hub on input shaft is engaged with input shaft fifth gear
mounted on the input shaft. The double cone synchronizing mechanism is provided
to 2nd gear synchromesh device for high performance of shifting to 2nd gear. The
countershaft turns the final gear and differential assembly, thereby turning the front
drive shafts which are attached to the front wheels.
The Components of a Transmission System are
· Clutch
· Gear Box/Transaxle
· Differential
· Drive Shaft/Axle
· Propeller Shaft
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12. · Transfer Gear Box
3.1 ADVANTAGES
· Cars with M/T are cheaper to buy
· Gives higher fuel efficiency
· Has lower maintenance cost
· Gives complete control to driver
3.2 CLUTCH
3.2.1. Construction
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13. The clutch is a diaphragm spring clutch of a dry single disc type. The diaphragm
spring is of a tapering-finger type, which is a solid ring in the outer diameter part,
with a series of tapered fingers pointing inward. The disc, carrying four torsional coil
springs, is positioned on the transaxle input shaft with an involute spline fit. The
clutch cover is secured to the flywheel, and carries diaphragm spring in such a way
that the peripheral edge part of the spring pushes on the pressure plate against
flywheel (with the disc in between), when the clutch release bearing is held back.
This is the engaged condition of the clutch. Depressing the clutch pedal causes the
release bearing to advance and pushes on the tips of the tapered fingers of the
diaphragm spring. When this happens, diaphragm spring pulls the pressure plate
away from flywheel, thereby interrupting the flow of drive from flywheel through
clutch disc to transaxle input shaft.
The three main parts of clutch are:
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14. 1. Driving member: consists of a flywheel mounted on the engine crank shaft.
The flywheel is bolted to cover which carries a pressure plate or driving disc,
pressure springs and releasing levers.
2. Driven member: consists of a disc or plate called clutch plate. It is free to
slide length wise on the splines of the clutch shaft.
3. Operating member: consists of a foot pedal, linkage, release or throw-out
bearing, release levers and springs necessary to ensure the proper operation of
the clutch.
3.2.2. Clutch System Symptoms Diagnosis
3.3. Gear Box in Front Wheel Drive or Transaxle
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15. A separate clutch shaft drives the input shaft via a splined coupling. The gears on the
countershaft are meshed with the gears on the input/main shaft. In a transaxle the
drive is directly transmitted to the differential.
· Reverse gear shaft is generally located in the gear box above the input shaft.
· The reverse idler gear is located on this shaft.
· The idler gear is meshed with the reverse gear to reverse the motion of the
vehicle.
3.4. Gear Box in Rear Wheel Drive
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16. A separate clutch shaft drives the input shaft via a splined coupling. The gears on the
countershaft are meshed with the gears on the main shaft. In this reverse shaft is
below countershaft.
3.5. Gear Shift Lever
· The gear shift lever is present inside the drive compartment of the vehicle.
· The purpose of a gear shift lever is enable the driver to select different
gears during the drive.
· The car may have 4 or 5 forward gears and a reverse gear which can be
selected as per the driving needs.
· Gear shift lever mechanism is of 2 types:
1. Direct shift type
2. Indirect shift type
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17. 3.5.1. Indirect Shift Type
· In this type of shifting mechanism a cable or a rod connects the lever to
the transmission.
· This type of shifting mechanism is generally used in front wheel drive
vehicles.
3.5.2. Direct Shift Type
.
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18. · In this type, the shift lever is connected directly to the transmission.
· This type of shift lever mechanism is used in rear wheel drive vehicles.
3.6. Shift Fork
· The shift fork is connected to the gear shift shaft, it is used to engage the hub
assembly with the selected gear.
· The shift fork is connected to the gear shift lever by the shift shaft.
· When the gear is selected the corresponding shift forks which are connected
to the shift shaft also move.
· During a gear change one shift fork moves one hub assembly away from the
gear and another shift fork moves the hub assembly for the newly selected
gear.
3.7. Gear Shift Control Lever and Cable Components
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19. 3.8. Gear Shift and Select Shaft Assembly components
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20. 3.9. Gear Shift Mechanism
The gear shifting control system consists of the following main parts. Movement of
gear shift control lever assembly (16) is transmitted to gear shift & select shaft
assembly (10) through gear shift control cable (1) and gear select control cable (2).
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21. 3.9.1. 5th & Reverse Gear Shift Cam
5th & reverse gear shift cam, cam guide return spring and 5th to reverse interlock
guide bolt are provided to prevent the gear from being directly shifted from 5th to
reverse.
· When shift lever is at neutral position between 3rd and 4th gear, 5th & reverse
gear shift cam (2) is under 5th to reverse interlock guide bolt (5) and can turn
freely clockwise (to 3rd gear) and counterclockwise (to 4th gear).
· When shift lever is shifted toward right from neutral position, shift & select
shaft (1) moves up but 5th & reverse gear shift cam (2) is restricted by 5th to
reverse interlock guide bolt (5) and return spring (3) is contracted.
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22. · When shift lever is shifted to 5th gear, shift & select shaft (1) turns clockwise
letting 5th & reverse gear shift cam (2) off from guide bolt and pushed up by
return spring (3). In this state, movement of shift cam is restricted by 5th to
reverse interlock guide bolt (5) and therefore, gearshift to reverse is not
attainable.
· When shift lever is shifted from neutral position between 5th gear and reverse
gear to reverse gear, 5th & reverse gear shift cam (2) turns counterclockwise
to attain reverse gear.
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23. 3.10. Input Shaft And Counter Shaft Assembly components
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24. 3.10.1. Input shaft
· Input shaft is a cylindrical shaped body which is used to transmit the power
from the clutch to the gear box.
· The drive received from the clutch is transmitted through a system of gears to
the countershaft.
3.10.2. Countershaft/Lay shaft
· Counter shaft or lay shaft is a cylindrical metal body which runs parallel to
the main shaft.
· Countershaft has a set of gears splined onto its surface.
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25. · The gears on the countershaft are meshed with the gears on the input/main
shaft.
· In a transaxle the drive is directly transmitted to the differential.
3.10.3. Main Shaft/Output Shaft
· Main shaft is cylindrical shaped metal body which transmits the drive from
the gear box to the differential.
· Gears are splined on its surface and are connected to the countershaft.
· The rotation of the main shaft with respect to the input shaft is controlled by
the gear ratio.
· The above type of arrangement is generally found in rear wheel drive
vehicles.
3.11. Gear Box
The following types of gear box are used in automobiles:
1. Sliding Mesh
2. Constant Mesh
3. Synchromesh
3.11.1. SLIDING MESH GEAR BOX
It is the simplest gear box. The following figure shows 4-speed gear box in neutral
position. 4 gears are connected to the lay shaft/counter shaft. A reverse idler gear is
mounted on another shaft and always remains connected to the reverse gear of
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26. countershaft. This “H” shift pattern enables the driver to select four different gear
ratios and a reverse gear.
Gears in Neutral:
When the engine is running and clutch is engaged the clutch shaft gear drives the
countershaft gear. The countershaft rotates opposite in direction of the clutch shaft. In
neutral position only the clutch shaft gear is connected to the countershaft gear. Other
gears are free and hence the transmission main shaft is not turning. The vehicle is
stationary.
First or low shaft gear:
By operating the gear shift lever the larger gear on the main shaft is moved along the
shaft to mesh with the first gear of the counter shaft. The main shaft turns in the same
direction as that of the clutch shaft. Since the smaller countershaft is engaged with
larger shaft gear a gear reduction of approximately 4:1 is obtained i.e. the clutch shaft
turns 4 times for each revolution of main shaft.
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27. Second speed gear
By operating the gear shift lever the third gear on the main shaft is moved along the
shaft to mesh with the third gear of the counter shaft. The main shaft turns in same
direction as clutch shaft. A gear reduction of approximately 3:1 is obtained.
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28. Third speed gear
By operating the gear shift lever, the second gear of the main shaft and countershaft
are demeshed and then the third gear of the main shaft are forced axially against the
clutch shaft gear. External Teeth on the clutch shaft gear mesh with the internal teeth
in the third and top gear. The main shaft turns in same direction as clutch shaft. A
gear reduction of approximately 2:1is obtained i.e. the clutch shaft turns 2 times for
each revolution of main shaft.
.
Fourth speed gear/ Top or High-Speed Gear
By operating the gear shaft lever the third gears of the main and countershaft is
demeshed and the gears present on the main shaft along with the shaft is forced
axially against the clutch shaft gear. External teeth present on the main shaft engage
with the internal teeth present on the main shaft. The main shaft turns along with the
clutch shaft and a gear ratio of approximately 1:1 is obtained.
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29. Reverse gear
By operating the gear shift lever, the last gear present on the main shaft is engaged
with the reverse idler gear. The reverse idler gear is always in mesh with the counters
haft gear. Interposing the idler gear between the counter-shaft reverse gear and main
shaft gear, the main shaft turns in the direction opposite to the clutch shaft. This
reverses the rotation of the wheels so that the wheel backs.
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30. Page 30

31. 3.11.2. CONSTANT MESH GEARBOX
In this type of gear box, all gears of the main shaft are in constant mesh with the
corresponding gears of the countershaft (Lay shaft). Two dog clutches are provided
on the main shaft- one between the clutch gear and the second gear, and the other
between the first gear and reverse gear. The main shaft is splined and all the gears are
free on it. Dog clutch can slide on the shaft and rotates with it. All the gears on the
countershaft are rigidly fixed with it.
When the left hand dog clutch is made to slide to the left by means of the gear shift
lever, it meshes with the clutch gear and the top speed gear is obtained. When the left
hand dog clutch meshes with the second gear, the second speed gear is obtained.
Similarly by sliding the right hand dog clutch to the left and right, the first speed gear
and reverse gear are obtained respectively. In this gear box because all the gears are
in constant mesh they are safe from being damaged and an unpleasant grinding sound
does not occur while engaging and disengaging them.
3.11.3. SYNCROMESH GEAR BOX
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32. In sliding Mesh Gear box the two meshing gears need to be revolve at equal
peripheral speeds to achieve a jerk less engagement and it is true for constant mesh
gear box in which the peripheral speeds of sliding dog and the corresponding gear on
the output shaft must be equal. The peripheral speed is given by:
ν= лd1N1=лd2N2
Where d1 and N1 are pitch circle diameter and r.p.m. of gear and d2 and N2 diameter
and r.p.m. of attached dog respectively. Now N1 ≠ N2 since d1 ≠ d2. Thus there is a
difference in gear and dog which necessitates double declutching. The driver has to
disengage the clutch twice in quick succession therefore it is referred as double
declutching. There are two steps involved in this process:
1. The clutch is disengaged i.e. first declutching and the gear system is placed in
its neutral position. Now the clutch is reengaged and acceleration pedal is
pressed to adjust the engine speed according to driver’s judgment.
2. The clutch is disengaged(i.e. second declutching) again the appropriate gear is
engaged and then the clutch is re-engaged.
It is that gear box in which sliding synchronizing units are provided in place of
sliding dog clutches as in case of constant mesh gear box. With the help of
synchronizing unit, the speed of both the driving and driven shafts is synchronized
before they are clutched together through train of gears. The arrangement of power
flow for the various gears remains the same as in constant mesh gear box. The
synchronizer is made of frictional materials. When the collar tries to mesh with the
gear, the synchronizer will touch the gear first and use friction force to drive the gear
to spin at the same speed as the collar. This will ensure that the collar is meshed into
the gear very smoothly without grinding.
Synchromesh gear devices work on the principle that two gears to be engaged are
first bought into frictional contact which equalizes their speed after which they are
engaged readily and smoothly. The following types of devices are mostly used in
vehicles:
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33. i. Pin Type
ii. Synchronizer ring type
A synchronizing system is used for smooth meshing. Synchromesh works like a
friction clutch. In the following figure two conical surfaces cone-1 is the part of the
collar and the cone-2 is the part of the gear wheel. Cone1, 2 are revolving at different
speeds. While cone-2 is revolving, cone-1 gradually slides into it. Friction slows or
speeds up the gear
wheel. Finally both the
cones revolve at same
speed.
In the following Fig. collar and gear wheel are separate and they are revolving at
different speeds. The internal cone comes in contact with the outer cone of the gear
wheel. Friction slows or speeds up the gear wheel.
And when the collar and gear wheel rotate at same speed the spring loaded outer ring
of the collar is pushed forward. The dog slides smoothly into mesh without clashing.
The collar and gear wheel lock and revolve at same speed. This is the principle of
synchromesh.
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34. The advantage of this type of gear
transmission has an advantage of
allowing smooth and quick shifting
of gears without quick shifting gears
without danger of damaging of gears
and without necessity for double
clutching.
3.12. The Drive Shaft
The drive shaft, or propeller shaft, connects the transmission output shaft to the
differential pinion shaft. Since all roads are not perfectly smooth, and the
transmission is fixed, the drive shaft has to be flexible to absorb the shock of bumps
in the road. Universal, or "U-joints" allow the drive shaft to flex (and stop it from
breaking) when the drive angle changes.
Drive shafts are usually hollow in order to weigh less, but of a large diameter so that
they are strong. High quality steel, and sometimes aluminum are used in the
manufacture of the drive shaft. The shaft must be quite straight and balanced to avoid
vibrating. Since it usually turns at engine speeds, a lot of damage can be caused if the
shaft is unbalanced, or bent. Damage can also be caused if the U-joints are worn out.
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35. There are two types of drive shafts, the Hotchkiss drive and the Torque Tube Drive.
The Hotchkiss drive is made up of a drive shaft connected to the transmission output
shaft and the differential pinion gear shaft. U-joints are used in the front and rear.
The Hotchkiss drive transfers the torque of the output shaft to the differential. No
wheel drive thrust is sent to the drive shaft. Sometimes this drive comes in two pieces
to reduce vibration and make it easier to install (in this case, three U-joints are
needed).The two-piece types need ball bearings in a dustproof housing as center
support for the shafts. Rubber is added into this arrangement for noise and vibration
reduction.
The torque tube drive shaft is used if the drive shaft has to carry the wheel drive
thrust. It is a hollow steel tube that extends from the transmission to the rear axle
housing. One end is fastened to the axle housing by bolts. The transmission end is
fastened with a torque ball. The drive shaft fits into the torque tube. A U-joint is
located in the torque ball, and the axle housing end is splined to the pinion gear shaft.
Drive thrust is sent through the torque tube to the torque ball, to transmission, to
engine and finally, to the frame through the engine mounts. That is, the car is pushed
forward by the torque tube pressing on the engine.
3.13. Differential Gear Box
Differentials are a variety of gearbox, almost always used in one of two ways. In one
of these, it receives one input and provides two outputs; this is found in every
automobile. In automobile and other wheeled vehicles, the differential allows each of
the driving wheels to rotate at different speeds, while supplying equal torque to each
of them. In the other, less commonly encountered, it combines two inputs to create an
output that is the sum (or difference) of the inputs. In automotive applications, the
differential and its housing are sometimes collectively called a "pumpkin" (because
the housing resembles a pumpkin).
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36. 3.13.1. Purpose
The differential gear box has following functions:
1. Avoid skidding of the rear wheels on a road turning.
2. Reduces the speed of inner wheels and increases the speed of outer wheels,
while drawing a curve.
3. Keeps equal speeds of all the wheels while moving on a straight road.
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37. 4.
Eliminates a single rigid rear axle, and provides a coupling between two rear
axles.
Power is supplied from the engine, via the transmission or gearbox, to a drive
shaft termed as propeller shaft, which runs to the differential. A spiral
bevel pinion gear at the end of the propeller shaft is encased within the differential
itself, and it meshes with the large spiral bevel ring gear termed as crown wheel. The
ring and pinion may mesh in hypoid orientation. The ring gear is attached to a carrier,
which holds what is sometimes called a spider, a cluster of four bevel gears in a
rectangle, so each bevel gear meshes with two neighbors and rotates counter to the
third that it faces and does not mesh with. Two of these spider gears are aligned on
the same axis as the ring gear and drive the half shafts connected to the
vehicle's driven wheels. These are called the side gears. The other two spider gears
are aligned on a perpendicular axis which changes orientation with the ring gear's
rotation. These two gears are just called pinion gears, not to be confused with the
main pinion gear. (Other spider designs employ different numbers of pinion gears
depending on durability requirements.) As the carrier rotates, the changing axis
orientation of the pinion gears imparts the motion of the ring gear to the motion of
the side gears by pushing on them rather than turning against them (that is, the same
teeth stay in contact), but because the spider gears are not restricted from turning
against each other, within that motion the side gears can counter-rotate relative to the
ring gear and to each other under the same force (in which case the same teeth do not
stay in contact).Thus, for example, if the car is making a turn to the right, the main
ring gear may make 10 full rotations. During that time, the left wheel will make more
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38. rotations because it has further to travel, and the right wheel will make fewer
rotations as it has less distance to travel. The side gears will rotate in opposite
directions relative to the ring gear by, say, 2 full turns each (4 full turns relative to
each other), resulting in the left wheel making 12 rotations, and the right wheel
making 8 rotations. The rotation of the ring gear is always the average of the
rotations of the side gears. This is why if the wheels are lifted off the ground with the
engine off, and the drive shaft is held (preventing the ring gear from turning inside
the differential), manually rotating one wheel causes the other to rotate in the
opposite direction by the same amount. When the vehicle is traveling in a straight
line, there will be no differential movement of the planetary system of gears other
than the minute movements necessary to compensate for slight differences in wheel
diameter, undulations in the road (which make for a longer or shorter wheel path),
etc.
3.13.2. Loss of Traction:
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39. One undesirable side effect of a differential is that it can reduce overall torque - the
rotational force which propels the vehicle. The amount of torque required to propel
the vehicle at any given moment depends on the load at that instant - how heavy the
vehicle is, how much drag and friction there is, the gradient of the road, the vehicle's
momentum and so on.
3.14. Transfer Gear Box
 The function of the transfer gear box is to distribute the torque generated in
the engine to all four wheels of the vehicle.
 The transfer gear box is controlled by the driver, the control is located in the
vehicle compartment it is either in the form of a transfer lever or a button.
 The transfer gear box connects the drive from the engine to the second
propeller shaft which transmits power to the front wheels of the vehicle.
3.15. DEFECTS IN GEAR BOX
The defects encountered in a Manual Transmission System are
· Abnormal Noise
· Gear Engagement and Disengagement Problems
· Gear Jumping Out
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40. · Oil Leakage
3.16. Manual Transmission Symptom Diagnosis
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41. 4. AUTOMATIC TRANSMISSION
Automatic transmission or A/T has no clutch. It changes gears automatically as
vehicle moves, thus freeing the driver from hassle of shifting gears. This automatic
transmission is electronic full automatic transaxle with forward 4-speed and reverse
1-speed .The torque convertor is a 3 element,1-step and 2 phase type and is equipped
with an automatically controlled lock up mechanism.
The gear change device consists of a ravigenau type planetary gear unit 3 multiple
disc type clutches,3 multiple disc type brakes and 2 one way clutches.
The hydraulic pressure control device consists of valve body assembly, pressure
solenoid valve (linear solenoid), 2 shift solenoid valves, TCC solenoid valves (TCC
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42. pressure control solenoid valve) and a timing solenoid valve. Optimum line pressure
complying with engine torque is produced by the pressure control solenoid valve in
dependence upon control signal from transmission control module (TCM). This
makes it possible to control the line pressure with high accuracy in accordance with
engine power and running conditions to achieve smooth shifting characteristics and
high efficiency.
A clutch-to-clutch control system is provided for shifting between third and fourth
gear. This clutch-to-clutch control system is made to function optimally, so that
hydraulic pressure controls such as shown below are conducted.
When upshifting from 3rd to 4th gear, to adjust the drain hydraulic pressure at
releasing the forward clutch, a timing solenoid valve is used to switch a hydraulic
passage with an orifice to another during shifting.
When downshifting from 4th to 3rd gear to adjust the line pressure applied to forward
clutch at engaging the forward clutch, a timing solenoid valve is used to switch a
hydraulic passage with an orifice to another during shifting.
When upshifting from 3rd to 4th gear with engine throttle opened, to optimise the line
pressure applied to the forward clutch at releasing the forward clutch, the learning
control is processed to compensate the switching timing of the timing solenoid at
every shifting.
When downshifting from 4th to 3rd gear with engine throttle opened, to optimize the
line pressure applied to the forward clutch, the learning control is processed to
compensate the line pressure ate every shifting.
4.1. DESCRIPTION
Page 42

43. 81-40LS
3-element, 1-step, 2-phase with lock-up mechanism
2.0
2400 +/- 150 rpm
Forward 4-speed, rev. 1-speed, Ravigneau planetary gear
1st 2.875 Front sun gear 24
2nd 1.568 Rear sun gear 30
3rd 1.000 Long pinion gear 20
4th 0.697 Short pinion gear 19
Rev 2.300 Ring gear 69
One way clutch
1.023
4.277
Direct cable shifting
Neutral, output shaft fixed, engine start
Reverse
Neutral, output shaft free, engine start
Forward 1st <--->2nd<--->3rd<--->4th automatic shift
Forward 1st <--->2nd<--->3rd (<---4th) automatic shift
Forward 1st <--->2nd(<---3rd) automatic shift
Forward 1st (<---2nd<---3rd) fixed
Radiator-assisted cooling (water cooling)
Page 43
Primary
Final
P
RND32L
Type
Position
Type
Drive
Type
Type
Capacity
2 sets
Number of teeth
Wet type multi-plate clutch
Wet type multi-plate brake
SUZUKI ATF 3317 or MOBIL 3309
Type
Type
Stall torque ratio
Stall speed
Torque converter
Forced pumping type by oil pump
Transmission
Shift mechanism
5.8 litres
Type
Control components
Reduction
ratio
3 sets
3 sets
Internal involute gear (non-crescent)
Engine-driving
Gear ratio
Oil pump
Cooling type
Lubrication Lubricant

44. 4.2. FUNCTION OF COMPONENTS
1.Input shaft
2.Front sun gear
3.Rear sun gear
4.Planetary long pinion
5.Planetary short pinion
6.Planetary carrier
7.Ring gear
8.Counter drive gear
9.Counter driven gear
10.Differential drive pinion
Page 44

45. Symbol Part name Function
C1 Forward clutch Meshes intermediate shaft with front sun gear
C2 Direct clutch Meshes input shaft with planetary carrier
C3 Reverse clutch Meshes intermediate shaft with rear sun gear
B1 O/D & 2nd brake Fixes rear sun gear
B2 Second brake Fixes rear sun gear
B3 1st & reverse brake Fixes planetary carrier
F1 One-way clutch No.1 Prevents rear sun gear form turning counterclockwise when B2 is active
F2 One-way clutch No.2 Prevents planetary carrier from turning counterclockwise
4.3. AUTOMATIC TRANSMISSION MODES
In order to select the mode, the driver would have to move a gear shift lever located
on the steering column or on the floor next to him/her. In order to select gears/modes
the driver must push a button in (called the shift lock button) or pull the handle (only
on column mounted shifters) out. In some vehicles position selector buttons for each
mode on the cockpit instead, freeing up space on the central console. Some of the
common modes are:
S1 S2 ST C1 C2 C3 B1 B2 B3 F1 F2
Shift
solenoid
valve
No.1
Page 45
Shift
solenoid
valve
No.2
TCC
solenoid
valve
Forward
clutch
Direct
clutch
Reverse
clutch
O/D &
2nd
coast
brake
2nd
brake
1st &
reverse
brake
One-way
clutch
No.1
One-way
clutch
No.2
O O X X X X X X X X X
O O X X X O X X O X X
O O X X X X X X X X X
1st O O X O X X X X X X O
2nd O X X O X X X O X O X
3rd X X + O O X X O X X X
4th X O + X O X O O X X X
1st O O X O X X X X X X O
2nd O X X O X X X O X O X
3rd X X + O O X X O X X X
2
1st O O O O X X X X X X O
2nd O X X O X X O O X O X
L 1st O O O O X X X X O X O
P
RN
D
3
Solenoid Brake / Clutch / OWC
O ON Engaged
X OFF Free
+ ON only when TCC is operating

46. 4.4. ELECTRONIC CONTROL
The electronic control system consists of:
· Valve Body Components
· Solenoid Operation
· Input / Output Table
· Control Details
4.4.1. Valve Body Components
· A/T range switch
There is no terminal for range “3”.
This SW informs starter, reverse lamp and TCM of A/T range to provide the
following functions:
· E/G starts in “P” and “N” range only.
· Reverse lamp turns on in “R” range.
· Range signal is used for gear shift control.
· Shift solenoid No.1, No.2 (S1,S2)
TCM actuate these solenoids to perform gear shift control.
Page 46
1. N” reference line
2. Lock washer needle
3. Sensor bolt
4. Manual select lever

47. · Timing solenoid (ST)
Timing solenoid switches timing valve to:
· apply hydraulic pressure to C1 clutch (C1:Forward clutch).
· control hydraulic pressure at C1 clutch drain orifice.
· Output/input speed sensor
Page 47
S1, S2: Normal open type
Current OFF: Valve open
Current ON: Valve closed
ST : Normal close type
Current OFF : Valve closed
Current ON : Valve open

48. · Output speed sensor : Differential gear speed
· Input speed sensor : C2 drum speed
· ATF temperature sensor
Automatic Transmission Fluid temperature signal is sent to TCM for gear
shift control and hydraulic pressure control.
Page 48

49. · Pressure control solenoid (SLT)
Pressure control solenoid regulates the line pressure linearly according to the
signal from TCM.
.
· Lock up solenoid (SL)
Page 49

50. .
4.4.2. Solenoid Operation
4.4.3. Input / Output Table
1. Pressure control solenoid valve (SLT)
2. Shift solenoid valve "A" (S1)
3. Shift solenoid valve "B" (S2)
4. TCC pressure control solenoid valve (SL)
5. Timing solenoid valve (ST)
6. Temperature sensor clamp
7. Valve body assembly
8. Manual valve
9. Solenoid lock plate
10. O-ring
FLD : Apply ATF
X : Do not reuse
(a) : 11Nm
Page 50
Gear shift control
Shift timing control
Torque control
Slope shift control
Lock up control
Slip control
Overdrive inhibit control
Line pressure control
Overrun control
Reverse control
Squat control
Throttle position o o o o o o o
Coolant temperature o o o o
Engine torque o o o o
Engine speed o o o o
A/C ON/OFF o
Stop lamp switch o o o
Range "3" signal o o o o
I/O shaft speed o o o o o
Vehicle speed o o o o o o o o o
ATF temperature o o o o o o o
Shift switch o o o o o o o o o o o
Torque reduction request o
Slip control signal o
Shift solenoid No.1 o o o o o
Shift solenoid No.2 o o o o o
Timing solenoid o o o
Pressure control solenoid o o
Lock up solenoid o o
Input
Output
Control
Input/Output

51. 4.4.4. Control Details
o Gear Shift Control
Gear shift control is performed according to the gear shift schedule shown in the
Service Manual
o Shift Timing Control
· [Input]
o Engine speed signal
o Input shaft speed signal
o Output shaft speed signal
· [Output]
TCM performs the following controls:
o Timing solenoid ON/OFF control
o Line pressure control solenoid duty control
o Learning Control
TCM learns the followings:
o Engage pressure applied to clutches and brakes
o Relief pressure at clutches and brakes
o Timing of application and relief of pressure
· [Purpose]
Shift shock reduction
Page 51

52. a) Gear shifting without one-way clutch: between 3rd and 4th speeds
In: Input shaft
Out: Output shaft
C: Clutch
B: Brake
[A]Planetary gear free
(engine speed rises
unnecessarily)
[B]Planetary gear locked
b) Gear shifting with one-way clutch between 1st and 2nd, 2nd and 3rd
speeds
- Double engagement is avoided by one-way clutch
o Overdrive Inhibit Control
1. At Low temperature
In: Input shaft
Out: Output shaft
C: Clutch
B: Brake
F: One-way clutch
Page 52

53. Overdrive is inhibited at low temperature.
:ECT < 50oC
:20oC<ATF<130oC
For a faster warming up
2. At “L”, “2” or “3” range
Overdrive is inhibited at “L”, “2” or “3” range
o Slip Control
· Slip: Partial engagement of torque converter clutch (lock up clutch) although
TP-VSS state is out of “lock-up zone”.
· During Acceleration
- Gear position is at 3rd or 4th.
- Throttle position and vehicle speed are in slip control zone
- Throttle position and vehicle speed are out of lock up zone
- 40oC<ATF temperature<110oC
- Not driving on an up slope
· During deceleration
- Gear position is at 3rd or 4th.
- Throttle position is “idle”
- Engine speed > 1200 rpm
- Vehicle speed > 28km/h (at 3rd gear) or 41km/h (at 4th gear)
- 20oC<ATF temperature<110oC
- Not applying hard braking
o Squat Control
Gear is shifting to 2nd until the turbine torque is synchronized and then to 1st
when shifting from N to D to reduce a shock.
o Reverse Control
Page 53
Gear Neutral
1st 1st
2nd
N-D shift

54. When shifting the A/T select lever from “D”,”3”,”2”,”L” to “R” at 11km/h or
faster, reverse gear is not engaged to protect the automatic transmission.
o Overrun Control
When shifting the A/T select lever from D to 3, 2 or L during high speed
driving, TCM inhibits down-shifting until the vehicle speed goes down to the
specified level in order to prevent engine overrun and to protect automatic
transmission.
o Torque Control
· During shifting, engine torque will fluctuate and this will cause a shock.
· TCM sends torque reduction request signal to ECM when shifting starts.
· ECM retards the ignition timing to reduce the engine torque.
o Lock Up Control
Lock-Up OK condition
The following conditions are all met.
- Gear position is at 3rd or 4th.
- Throttle position and vehicle speed in a lock-up range at “D” or “3” range.
- ATF temperatures are above 60oC.
- Stop lamp switch is OFF
Lock-Up NG condition
One of the conditions above is not met.
Page 54
Ignition
timing
Retard

55. o Line Pressure Control
TCM controls pressure control solenoid with duty signal according to the
following signals:
-Engine speed signal (from ECM)
-Throttle position signal (from ECM)
-ATF temperature signal
-Input shaft speed signal
-Output shaft speed signal
Page 55
Lock up clutch status Throttle position Vehicle speed
Over 89% 103-108
50% 67-70
10% 39-44
Over 94% 93-98
50% 56-61
10% 35-40
Over 89% 139-144
50% 82-87
10% 53-58
Over 94% 129-134
50% 73-78
10% 51-56
3rd gear
lock up
4th gear
lock up
ON
OFF
ON
OFF

56. 5. AUTOMATIC MANUAL TRANSMISSION
A automatic-manual transmission (also known as clutch less manual transmission,
automated manual transmission) is a system which uses electronic sensors,
processors and actuators to do gear shifts on the command of the driver. This
removes the need for a clutch pedal which the driver otherwise needs to depress
before making a gear change, since the clutch itself is actuated by electronic
equipment which can synchronize the timing and torque required to make gear shifts
quick and smooth. a semi-automatic transmission can also be switched to manual
mode to perform gear shifting at the drivers wish. The two most common semi-automatic
transmissions are:
1. Direct shift transmission (or dual-clutch transmission).
2. Electro-hydraulic manual transmission (or sequential transmission).
5.1 Direct shift transmission
In direct shift transmission direct shift gear box is used. The Direct-Shift Gearbox or
D.S.G. is an electronically controlled, twin-shaft dual-clutch manual gearbox,
without a conventional clutch pedal, with full automatic or semi-manual control.
Unlike the conventional manual transmission system, there are two different
gear/collar sets, with each connected to two different input/output shafts. The outer
clutch pack drives gears 1, 3, 5 and reverse. It is just like two conventional manual
transmission gear boxes in one. The inner clutch pack drives gears 2, 4, and 6.
Instead of a standard large dry single-plate clutch, each clutch pack is a collection of
four small wet interleaved clutch plates.
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57. Due to space constraints, the two clutch assemblies are concentric. To automatically
shift from 1st gear to 2nd gear, first the computer detects that the spinning speed of the
input shaft is too high, and engages the 2nd gear’s collar to the 2nd gear. The clutch
then disengages from 1st gear’s input shaft, and engages the 2nd gear’s input shaft.
Controlled by computer, the gear shift becomes extremely fast compared with a
conventional manual transmission. Using direct contact of the clutch instead of fluid
coupling also improves power transmission efficiency.
Another advanced technology used for direct shift trans-mission allows it to perform
“double clutching” by shifting the gear to neutral first, adjusting the spinning speed
of the input shaft, and then shifting to the next gear. This makes gear shifting very
smooth.
5.2 Electro Hydraulic Manual Transmission
In electro-hydraulic manual transmission (also known as sequential transmission) the
gear set is almost the same as the conventional transmission system, except that the
shifting of the se-lector is not an “H” pattern. Instead, all selector forks are connected
to a drum. The drum has several grooves, and each has a ball sliding in it. Each fork
hooks up to a ball and can be moved forward and backward when the drum is
turning. Based on the pattern of the grooves on the drum, by turning the drum, each
Page 57

58. fork can move forward and backward in turn, which makes gear selection sequential.
Therefore, it is impossible for an electro-hydraulic manual transmission to perform a
gear shift from 1st to 3rd or 4th to 2nd. The shifting must be sequential, like 1st ▬► 2nd
▬► 3rd ▬►4th, or 4th▬►3rd▬►2nd▬►1st.
5.3 Advantages
· Freedom from operating the clutch lever.
· Very comfortable for stop and go traffic.
· Better mileage than automatic transmission.
· Lower cost than automatic transmission.
5.4 Disadvantages
· More expensive than manual transmission.
· Not widely available
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59. 6. CONTINUOUSLY VARIABLE TRANSMISSION
The continuously-variable transmission is also an automatic transmission system,
which changes the diameters of input shaft and output shaft directly, instead of going
through several gears to perform gear ratio change. This design can generate an
infinite number of possible gear ratios. Unlike the complicated planetary automatic
transmission system, a C.V.T. only has three major parts:
1. A drive pulley connected to the input shaft.
2. A driven pulley connected to the
output shaft.
3. A belt.
.
This transmission is only offered in Maruti’s Kizashi model .In CVT’s, cars use a
pair of variable-diameter pulleys, each shaped like a pair of opposing cones, with a
Page 59

60. metal belt or chain running between them. One pulley is connected to the engine
(input shaft), the other to the drive wheels (output shaft). The central component is
known as the variator: a transmission element resembling a V-belt connects two
axially adjustable sets of pulley halves. As the belt is a highly stressed component it
must be very strong and grip very well. These flexible belts are composed of several
(typically nine or 12) thin bands of steel that hold together high-strength, bow-tie-shaped
pieces of metal. They are also quieter than rubber-belt-driven CVTs. The
halves of each pulley are moveable; as the pulley halves come closer together the belt
is forced to ride higher on the pulley, effectively making the pulley's diameter larger.
Changing the diameter of the pulleys varies the transmission's ratio (the number of
times the output shaft revolves for each revolution of the engine), in the same way
that a 10-speed bike routes the chain over larger or smaller gears to change the ratio.
Making the input pulley smaller and the output pulley larger gives a low ratio (a large
number of engine revolutions producing a small number of output revolutions) for
better low-speed acceleration. As the car accelerates, the pulleys vary their diameter
to lower the engine speed as car speed rises.
6.1 Advantages of the CVT
· Ease of city Driving.
· Fuel economy similar to MT.
· Flexibility:
- Driving flexibility with Automatic and Manual modes.
- Two pedal drive for comfortable ride in start stop city traffic.
- Kick down function for meeting sudden acceleration requirement.
· Hassle free maintenance.
6.2 Disadvantages of the CVT
· Many drivers to not like it because you do not feel the engine accelerating.
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61. · Higher cost.
· Transmitting motion by friction causes greater wear.
· Require special oil and other materials.
7. ADVANCE FEATURES
7.1 Detent Pin Technology
For gear shifting mechanism “Detent Pin” technology is being used for
reduced friction, smoother gear shift & better gear shift feel.
7.1.1 Functions of Detent pin
· Location and positioning of the required gearshift position.
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62. · Locking in place once the gearshift position has been located.
· Ensuring precise and secure gearshift by means of a defined gearshift
resistance.
· Communicating a positive gearshift feel to the driver and a clear
sensation that the gear has been engaged.
7.2 Diagonal Shift Assistance
Diagonal Shift Assist (DSA) adds to the comfort by assisting in
effortless shifting from 5th to 4th gear .
7.3 Reverse Shift Prevention
· The cubic projection on the gear shift and select lever is blocked by the
projection of reverse shift limit yoke when gear shift control lever is shifted
from 5th position to reverse position.
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63. · As cubic projection of gear shift and select lever pushes the reverse shift limit
yoke, the yoke rotates and pushes the cubic projection of the lever toward the
neutral position.
1. Gear shift and select lever
2. Reverse shift limit yoke
[A] : 5th
[B] : Reverse
[C] : 4th
· Gear is shifted into 4th position if gear shift and select lever is still pushed
toward reverse position. Reverse shift limit yoke returns to original position
by spring force.
7.4 Reverse Gear Actuation
Page 63

64. Weight for New reverse gear actuation mechanism has been reduced by
150gm making lightest in all MSIL models.
8. CASE STUDY
MODEL MILEAGE VEHICLE SYSTEM
SX4 VDI 3664 Kms Transmission
Problem
A repeat complaint was received from the customer for fifth gear slippage in SX4-D
vehicle.
Observation
Vehicle was brought to the workshop and the defect mentioned by the customer was
confirmed during the road test.
Action Taken
· The problem of 5th gear slippage reported by the customer was confirmed
during the road test.
Page 64

65. · Vehicle history was checked and it was found that vehicle had reported for
similar complaint at a mileage of 2890 Kms.
· As per vehicle history only circlip was changed during previous visit.
· Gear box was opened and 5th gear assembly was checked.
· 5th gear snap ring was found damaged.
· It caused improper meshing between fifth gear and its counter gear, which
caused chipping off or deep scoring on the gears.
· All the affected parts (gear, countershaft 5th, gear, input shaft 5th, circlip hub
assy, 5th speed sync, bearing,5th gear needle , ring, synchronizer) were
replaced
· Proper road test was taken and performance of the vehicle was found
satisfactory.
Root cause
Gear slippage was due to breakage of the circlip which resulted in improper meshing
of gears and chipping of gear teeth.
Remark
Thus in order to rectify such defect in one visit casual part (circlip) as well as
affected part (fifth gear) should be replaced.
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66. 9. CONCLUSION
The 6 weeks Industrial Training at “Maruti Suzuki Training Centre “was indeed the
most learning experience”. It provided me an opportunity to learn practical
application of my technical knowledge. I learnt a lot about automobile in basic
training and worked on transmission in cars. I learnt about different types of
transmission which are used in Maruti cars and the problems concerned with the
latter. During the training, I learnt of their advantages and disadvantages and the
advance features that Maruti Suzuki is introducing for customer satisfaction. Maruti
stands for the customer satisfaction in the market. Maruti Suzuki’s Tagline” WAY
OF LIFE” symbolize the changes within Suzuki. In addition, I gained a good
experience in term of self confidence, real life working situation, interactions among
people in the same field and working with others with different professional
background. I had an interest in understanding basic engineering work and practicing
Page 66

67. what has been learnt in the class. Also, the training was an opportunity for me to
increase my human relation both socially and professionally.
Page 67

68. 10. REFERENCES
[1] http://www.auto.howstuffworks.com
[2] http://www.google.com
[3] http://en.wikipedia.org
[4] http://www.answers.com/
[5] http://www.familycar.com
[6] www.edmunds.com
[7] www.scribd.com
[8] www.workshopsmanual.com
[9] www.motorera.com
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69. Page 69