Page 72 of 425
Transmission-33
10. Remove the high and low gear drive declutch shift shaft
11.Remove the second and fourth drive declutch shift shaft
12. Use the plastic hammer to knock out the rear output shaft
assembly, front output shaft assembly and chain out slightly
13. Remove the second/fourth shift block and high and low gear
shift fork
14. Remove the housing of transfer case
a. Use the wrench to remove 4 bolts M10
1.2535 and 2 nuts
M10
1.25 connected the gearbox and tranafer case housing
Caution: The tightening torque is 30
42 N•m when install
the connecting bolt of gearbox and housing of transfer case
Page 74 of 425
Transmission-35
Disassembly of rear output shaft assembly
a. Use the special tools to remove the lock nut
Caution: The tightening torque is 87-120N
m when in-
stall the lock nut.
b. Remove the ball bearing
Rear output shaft assembly
cRemove the oil guide plate
circlips for shafthigh and low
gear sleeve
needle bearing
high and low gear hub
needle bearing
low-speed driven gear
rear output shaft
ball bearing
spacing platesecond/ fourth drive gear hub
second/fourth
drive geared sleeve
sprocket needle bearing bushing
needle
bearing
drive sprocket
spacer of
drive sprocket
oil guide plate assembly
ball bearing
assembly
87-120
N m: specified torque
Used component which can not be used any more.
Use the special tools
dRemove the spacing ring
Page 78 of 425

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.
Page 79 of 425
Automatic transmission-3
8. Use two bolts to install the back device on the extended case of the transmission, these lengths are important. If it is too long,
it will hinder the end of the bolt and affect the threads on the case. Ensure the proper length and special torque of the bolt.
9. Pay attention that the height of the oil has been determined before delivery from the ION Company. The oil height needs not
checking or correction, except that improper oil is suspected to be used, or additional oil is needed because of leakage.
Page 80 of 425

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.
Page 83 of 425

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
Page 87 of 425

Automatic transmission-11
Diagnosis input
solenoid valve
1and 2 S1 and S2 is the normal open solenoid valve, which is used to set the gear-position with other switch
solenoid valve. It determines the static gear-position by operating the gear shift valve. Refer to Table 3.5,
S1 and S2 also send the pressure single to allow or prohibit the engagement with rear brake belt.
solenoid valve
3and 4 S3 and S4 are the normal-opened solenoid valve which is used to control the shifting quality and sequence in
combination. S3 control the open or close of the clutch. S4 is used to control the on and off of the front brake
belt regulating valve.
solenoid valve 5 S5 is the variable pressure solenoid valve which can release the pressure of gear-position shifting. It provides
the pressure signal to the clutch and brake belt regulator and controls the shifting pressure. S5 also provides
the pressure single to the torque converter clutch regulating valve.
solenoid valve 6 S6 is the normal-opened solenoid valve, which is used to the set the H/L level of pipeline pressure. The
pipeline pressure is high when the solenoid valve is closed.
solenoid valve 7 S7 is the normal-opened solenoid valve which is used to control the engagement status of torque converter
licking clutch. It makes the clutch to generate the action when the S7 is in opened status.
Table 3.4 Status and function of solenoid valve
Gear-position S1 S2
1st-Gear On On
2nd-Gear Off On
3rd-Gear Off Off
4th-Gear On Off
R-Gear One of them is in On position
at least.
N-Gear Off Off
P-Gear Off Off
Table 3.5 Logic status of solenoid valve in static gear-position
Page 88 of 425
Automatic transmission-12
Shifting Initial shifting status Current variation of S5 Finished shifting status
1-2 S1 Off
S4 On 950mA-650mA
S4 Off
1-3 S1 Off
S2 Off
S3 On
S4 On 900mA-400mA
S3 Off
S4 Off
1-4 S2 Off
S3 On
S4 On 850mA-750mA
S3 Off
S4 Off
2-3 S2 Off
S3 On
S4 On 700mA-200mA
S3 Off
S4 Off
3-4 S1 On
S4 On 950mA-550mA
S4 Off
4-3 S4 On 950mA-700mA S1 Off
S4 Off
4-2 S3 On 800mA-500mA S1 Off
S2 On
S3 Off
4-1 S3 On
S4 On 1000mA-600mA
S2 On
S3 Off
S4 Off
3-2 S2 On
S4 On 550mA-400mA @ 20kph
800mA-600mA@60kph
1000mA-800mA@100kph S4 Off
3-1 S3 On
S4 On 1000mA-750mA S1 On
S2 On
S3 Off
S4 Off
2-1 S4 On 1000mA-500mA S1 On
S4 Off
Torque converter clutch
On
Off S7 On 1000mA-500mA
900mA-600mA S7 Off
Table 3.6 Operation of solenoid valve during shifting period