engine GREAT WALL HOVER 2006 Service User Guide

Clutch-2
Troubleshooting

failure cause inspection content
Shift difficulty or can not shift
Large free stroke of clut ch pedal clutch Pipe
has air
Failure of clutch cylinder
Failure of clutch master cylinder
The installation position of clutch disc is not
in position; large deviation; oil on the friction
lining or broken
The clutch disc is dirty or with foreign
material
Failure of clutch cover Adjust the free stroke of pedal
Discharge the air in clutch system
Replace
replace
Inspect the clutch disc; replace
Repair if necessary
Replace
Disengagement of transmission The clutch guide bearing is worn. Replace the guide bearing
Slide of clut ch
insufficient free stroke of clutch pedal
oil on the clutch disc friction lining or broken
failure of press disc
separation rocker arm assembly is blocked Adjust the free stroke of pedal
Inspect the clutch disc and replace it
Replace the clut ch cover
Check the separation rocker arm assembly
clutch clamping
stagnation/vibration oil on the clutch disc friction lining or broken
failure of press disc clutch membrane spring
is bend
loose of engine bracket Inspect the clutch disc and replace
Replace the clut ch cover
Correct the clutch membrane
Repair if necessary
Soft of clutch pedal clutch pip e has air
failure of clutch cylinder
failure of clutch master cylinder Discharge the air in clutch
replace
replace
Loud noise of clut ch
Component in clutch housing is loose
Throw-out bearing is worn or dirty
guide bearing is worn
separation rocker arm assembly or pull-rod is
blocked Repair if necessary
replace
replace
Repair if necessary

2. Operation of 4WD
The operating auxiliary steering column can be shifted to 4WD status.
For position of auxiliary steering column and corresponding operating
condition refer to table.
3. Caution for operation:
a. Do not use 4WD in good surface, otherwise the tyre and components
of drive system will be damaged easily and increase the consumption
of fuel, and cause the noise of drive system.
b. Please run in 1st-Gear under “4L” gear position when run in very
low speed in field.
Operating instruction of transmission SC5M4D-C
1.The schematic diagram of transmission operating gear position
is on the handle of steering column.
During the process after vehicle is started and in traveling, it must
step the clutch pedal to bottom before the shifting. If need shift from
5
th-Gear to reverse-Gear, it should move the shifting bar to the neutral
position of 3rd/4th-Gear. Shift to R-Gear after stop the vehicle stably,
otherwise, it can not shift.
During the traveling process. It should always pay attention to the
shifting to make the vehicle matches to the speed of engine. The
correct shifting can improve the economical efficiency and prolong
the service life of engine. Do not shift from high-Gear to low-Gear on
the condition that the pointer of tachometer may enter into red area,
otherwise, the engine will be damaged.
Warning: Do not shift to reverse-Gear when the vehicle moves
forwardly, otherwise the transmission will be damaged.
hand hall of main steering column
hand ball of auxiliary steering column
Auxiliary steering
column position drive Operating condition
2H 2WD Use this gear position when run in the general railway and high speed highway.
4H High speed 4WD Use this gear position when run in the deep snowland, sand ground or uneven road
in normal speed.
N Neutral gear When use the gear position during using of winch, it could not drive the vehicle.
4L Low speed 4WD Use this gear-position when run in uneven road such as mud land or climbing or
downward （especially when need increas e the power）.

Automatic transmission-2
Instruction for automatic transmission
1. M88 4-speed automatic transmission is equipped with the hydraulic torque converter and electric control system with locking.
When keep the stable forward status, the hydraulic torque converter can be locked automatically when the engine operates in low
speed, then reduce the unnecessary slide.
Figure 1.1 Electric automatic transmission control system
Figure 1.2 M88 4 speeds automatic transmission appearance figure (applied to 2 wheels driving)
2. The main advantage of the transmission is the application of transmission control unit (TCU). The control unit is the control
system based on the microprocessor system.. TCU control the shifting sensing and realize the Gear position shifting through the
signal of opening degree of throttle position, opening frequency of throttle position, engine speed, vehicle speed, transmission oil
temperature, gear position, mode selection and forced Gear reduction application.
3. TCU drives a variable pressure regulating solenoid valve to control three regulation valves and control the feeling of shifting.
Different transmission fluid temperatures are taken as one the main parameters to control the output pressure of the solenoid
valve, so as to keep consistent feeling of shifting within the normal operation scope.
4. The planning of shifting is very flexible. According to the car model, the different shifting plan is stored in the same TCU.
Generally speaking, the “economical mode” can increase the economical efficiency of the fuel and the driving performance of the
car to the maximum limit. The “dynamic mode” can bring into full play the drive performance of the car to the maximum limit. The
“winter mode” can make the car starting from shift 2.

Automatic transmission-4
10. The gross weight of the transmission is 76kg; mostly weight is on the front of the transmission (side of torque converter). This
should be considered when design the handling/assembly tools.
11. The crankshaft speed/position sensor is installed on the top of transmission torque converter housing which must be installed
after the transmission is installed on the engine. The sensor will be damaged if it is installed before the installation of
transmission.
12. The transmission use the breathing tube connected to rear end of transmission. The tube must not be restricted or blocked
otherwise the air pressure in transmission will be increased. It is unallowable that the water/dirty/dust enters into the
breathing tube; otherwise the transmission will be damaged.
Removal of transmission
If the transmission needs removing for any reasons, following is the preventive measure to help the remove.
1. Must not only support the oil pan in middle of transmission for it will be deformed and leaked. The oil pan will not be deformed
when supports its external edge.
2. It must not allow the transmission to connect to the engine when the rear end is without connection, otherwise the exhaust
system of vehicle will be damaged.
3. Remove all torque converter bolts and push back the torque converter before remove the bolt connected the torque converter
housing to engine. Once all bolts connected the torque converter housing to engine are removed, use the torque converter the
push the transmission from the location pin, then ensure the torque converter is on the transmission and the transmission is
separated form location pin.
4. Install the dustproof cover on the cooler connector rapidly after open the oil cooler pipe; otherwise the oil leakage from the
torque converter will be 2L. The odometer dustproof cover can prevent the dirty from entering into the transmission and avoids
the leakage of oil form transmission.
5. The engine speed sensor is installed on the top of transmission and should be removed before the transmission is removed form
the engine, for the sensor will be damaged during the removal process of the transmission.
Figure 2.1 Gear selection interface
mode selection
gear selection
indicationgear slide way
Operation and display interface
The four-speed automatic transmission has three types of operation display interface which are shown as follows:
Gear selection
The transmission uses the traditional gear selection shifting handle, which is shown in figure. The gear rod can be moved on the gear
slide way according to the requirement. The relationship between the related gear and its function.

Automatic transmission-5
Table 2.1 Gear selection and its function
Gear selection function
1st-Gear
(manual 1
st-Gear ) The first gear is using for climbing and braking. It is a function which limits the speed of
the car. The speed limitation by engine is realized by reduce the opening degree of
throttle position.
2nd-Gear (automatic, manual
2
nd-Gear) In economic mode, it can process the 1
st and 2nd shifting operation when engage the 2nd
–Gear. The limitation of vehicle speed by engine is realized through reducing the
opening of throttle position. in 4WD 4 high, , the transmission will maintain 2
nd-Gear
position The manual mode and winter-Mode will only maintain 2nd-Gear 。
3rd-Gear
(automatic, manual 3rd-Gea) In economic mode and dynamic mode, it can process the shifting operation of 1
st, 2nd
and 3rd-Gear when engage the 3rd-Gear, and can reaches the very high vehicle speed. At
this time the locking clutch can process the locking action, refer to vehicle user manual.
The limitation of vehicle speed by engine is realized by reduce the opening of throttle
position. In 4WD 4 low, the transmission should be maintained in 3
rd –Gear position.
Under manual mode, the transmission will be kept in 3rd-Gear.
D-gear
(drive) It can process the 1
st, 2nd, 3rd and 4th –Gear position operation and gear-shifting operation
of (1-2), (1-3), (2-3), (2-4), (3-4), (4-3), (4-2), (3-1) and (2-1). This shifting operation is
processed by taking the vehicle speed, throttle position, throttle position switching
frequency (or forced Gear-decreasing) as the parameter. The locking clutch can process
the locking action in 3rd –Gear, 4
th-Gear according to the type of vehicle. Refer to user
manual of vehicle.
N-Gear
(neutral gear) Only the rear brake belt is engaged at this time. It determines whether the function can
be realized according to the vehicle speed, engine speed and throttle position. But the
gear-position sensor allows the starting of engine. Allow the slide of N-Gear.
R-Gear
(reverse gear) Set the anti-misoperation in forward function according to the vehicle speed, engine
speed and throttle position opening to realize the reverse operation. The gear-position
sensor can start the revers e lamp.
P-gear
(parking gear) Only the rear brake belt is engaged at this time. The function can be determined
according to the vehicle speed, engine speed and throttle position. The output shaft of
transmission is locked. The gear-position sensor can start the engine.

Automatic transmission-6
Selection of drive mode
The selection of drive mode includes a mode selection switch and indicator lamp. The drive mode selection switch is located
on the operating panel. It can provide the different mode selection according to the different type of car.
It has the optimal fuel economy when select the “normal” mode. At this time, the indicator lamp is not light. When select the
“dynamic” mode, the car will have the maximum dynamic performance and the “dynamic” mode indicator lamp is light. When select
the “snowland” mode, it will realize the starting of “2
nd-Gear”, the “snowland” mode indicator lamp is light, meanwhile the
“dynamic” mode indicator lamp will be closed. When select the manual mode, press down the “snowland” switch firstly, the
“manual” light will be light when the gear is in 3, 2, 1. When in manual mode, 1-2, 2-3, 3-4, 3-2, 2-1, 1-3, 3-1 is shifted by driver
manually and can not be shifted automatically. It can be used in car-racing etc. for the special mode of each model of car refers to
operation manual of user.
Operation instruction
Function
5 Brake function
Can decrease the gear-position in slope to improve the brake effect and increase the vehicle safety.
6 Speed-up function
It can select the manual shifting to increase the vehicle speed completely during the speed-up.
cautions
7 It must place the transmission in the P-Gear or N-Gear when start the engine.
8 It must place the transmission in P-Gear during the parking.
9 It must place the transmission in N-Gear when trail the car.
10 It must be powered off when remove the transmission.
11 It must be powered off when install the transmission.
The transmission processes the communication and calculation with the engine electronic control computer by the precision
central on-line computer. It not only save the fuel, but also provide the maximum mode function, including field, winter and
manual selection. It provides the two conditions, manual and electric for the fast race of racing player. It has racing capacity wh i ch
can compete the speed increasing with the manual transmission.
automatic
Having anti-slide function
It is allowable that the D-Gear
in “W” mode is used in
snowland and M-A integration
mode. automatic
automatic

Automatic transmission-7
Indicator lamp
Figure 2.2
control system
General
The transmission has two sets of control system, a electric control system and a hydraulic control system. The electric control
system monitors the vehicle parameter and adjusts the transmission performance; the hydraulic control system executes the
command of electric control system.
Electric control system
The electric control system consists of the sensor, TCU and 7 solenoid valves. TCU read in the data and make the output under the
control of software based on the value stored in Read Only Memory (ROM).
TCU controls the hydraulic control system and the control is realized through the valve and pump assembly. The system includes
7 solenoid valves, in which 6 valves are used to control the line pressure, operate the shift valve and hydraulic torque converter lock
clutch and switch on and off two regulating valves (Two regulating valves control the shift feel). The seventh solenoid valve is the
pressure regulating solenoid valve (VPS) which controls the shift feel with other three regulating valves. Figure 3.1 is the typical TCU
control system plan.
The figure includes all elements of electric control system involved in the section.
throttle position
open sensor
Engine speed
vehicle speed
Transmission
fluid temperature
mode selection
(instrument panel
/console )
Gear sensor
Forced step-
decreasingK line
shifting
logic
shifting
sensing
line
pressurehydraulic
control
system
Solenoid valve 1
Solenoid valve 2
Solenoid valve 3
Solenoid valve 4
Solenoid valve 5
Solenoid valve 6
Solenoid valve 7
pressure regulating
solenoid valve
Mode indicator lamp
Gear indicator lamp
set and other
necessary equipment
indication

Automatic transmission-13
Symbol of solenoid valve (On/off solenoid valve)
Figure 3.5 Normal-opened type
1.Variable pressure regulating valve regulating system
The shifting pressure of abrasion unit is controlled by the variable pressure regulating valve.
The line pressure is independent of the shifting pressure and determined by the thro
position, shifting status and engine speed.
S5 is a proportional or variable pressure regulating valve which provides the pressure signal control shifting pressure for
the clutch and brake belt regulating valve.
In automatic shifting period, it process the integral times enlarging and contracting
regulation for the clutch regulating valve, brake belt regulating valve, torque converter regulating valve and VPS.
The hydraulic pressure generated by variable pressure regulating valve is in inverse ratio with current. During the shifting, TCU
will increase or decrease the current of solenoid valve according to the program. The current is variable in the range of 200mA
to 1000mA. The increasing of the current will decrease the S5 output pressure; the decreasing of current will increase the output
pressure of S5.
Lin 500 pressure (about 440 to 560kPa) is the reference pressure of VPS, meanwhile, the VPS output pressure equals to the
pressure on line 500 always.
When the VPS is in waiting status, it means there is not the generation of shifting action. VPS current is 200mA. At this time,
it gives the maximum output pressure.
In stable status, the brake belt and clutch regulating solenoid valve is in closed status. In this condition, the pressure of line 500
is applied on the piston. For the line 500 pressure is more than S5 pressure always, so it pushed the oil in S5 to the place
between the regulating valve and piston. At this time, oil pressure applied on the friction unit equals to the product of pressure
on line 500 and magnification factor.
During the starting of shifting, the used on/off solenoid valve is in opened status which cut off the oil loop supply from line 500
to piston.
At the same time, VPS pressure is decreased to starting pressure valve, pressure set by regulating valve and pressure setting
value required by execution of VPS by pushing the piston from the valve. The shifting is finished through the on/off solenoid
valve, VPS returns to the waiting status
Pointed to each gear-position, the system can make the brake belt; clutch or both realize
the electronic control.
Mode indicator lamp: the mode indicator lamp can be used to indicate the current selected and whether the overpeed status
exists. The mode indicator lamp is located in instrument panel generally. (Refer to Part 2.3)

Automatic transmission-19
Figure 3.15 clutch combination regulating valve
10. Brake belt combination regulating valve
aP-Gear or N-Gear, vehicle speed 3km/h
b
R-Gear , speed 10km/h
c
Speed of engine : 1250rpm
d
Diesel vehicle , Opening degree of throttle position: 25
eGasoline vehicle, opening degree of throttle position: 12
In this condition, the TCU control solenoid valve S1 and S2 are closed. The reverse lock valve is affected by the pressure form
S1-S2 transmission fluid; connect the line pressure to loop B2. The transmission fluid flows to servo internal and external
attachment area, the B2 is engaged.
When none of above condition is met, TCU control the solenoid valve S1 and S2 to be opened. The pressure of S1-S2 is
released and the spring control valve body is in locking status at the same. In this condition, the B2 attachment is prohibited.
The feature can realize the protection for transmission by controlling the B2 in high speed and providing the reverse-gear
locking.
If the transmission is in failure mode, then the rear brake belt will be attached in P-Gear, R-Gear and N-Gear.
Figure 3.16 brake belt combination regulating valve

Automatic transmission-20
Figure 3.17 reverse lock valve
12. Primary regulating valve
Primary regulating valve (PRV) (refer to Figure 3.18) can regulate the line pressure of transmission (or pump output
pressure). The valve can give the high or low line pressure according to the on/off status of S6. When S6 is in on or off status,
the pressure S6 is applied on PRV, move it and has the action of spring force. Open the line pressure loop to turn on the inlet
of pump to reduce the line pressure. Generally, the line pressure is small when the throttle position is opened lightly and in
patrol status. It will cause the closing of S6 when the opening degree of throttle position is large and because the high line
pressure valve
For all shifting pressures are controlled by output of separation brake belt , clutch regulating valve and S5, so all step control
of line pressure has not affect on effect of shifting sensing.
By the oil inlet of torque converter, PRV also adjust the oil supply of hydraulic torque converter. The level effect of PRV
should ensure the priority of valve, i.e. it can keep the line pressure in low engine speed condition. When the speed of engine
is increased and the pump supplies excess oil, the PRV acts to open the torque converter oil inlet cover to increase the pressure
of torque converter. If the oil amount is beyond the requirement of transmission, PRV will act further to allow the oil return
to the suction inlet.
Figure 3.18 Primary regulating valve
Figure 3.19 Torque converter on/off regulating valve
The torque converter regulating valve (refer to Figure 3.19) adjusts the pressure applied on torque converter clutch oil.
According to the signal pressure form loop S5, adjust the oil flow status from line pressure loop in valve. With the change of
pressure signal of loop S5, the engagement and disengagement of torque converter clutch can be finished by electric control.
13. Torque converter on/off regulating valve