2003 SSANGYONG MUSSO light

5A-24 AUTOMATIC TRANSMISSION
Transmission Control Unit(TCU)
The TCU is an in-vehicle micro-processor based transmission management system. It is usually mounted in the
vehicle cabin, under the instrument panel, under the seat, behind the side kick panels or under the floor in the
footwell on the passenger side. Different control units are supplied for different vehicle applications.The TCU contains:
Processing logic circuits which include a central microcontroller and a back-up memory system.
Input circuits.
Output circuits which control external devices such as the variable pressure solenoid (VPS), on/off solenoid
drivers, a diagnostics output and the driving mode indicator light.
The various items which make up the TCU are discussed below.
Processing Logic
Shift schedule and calibration information is stored in an erasable programmable read only memory (EEPROM).
Throttle input calibration constants and the diagnostics information are stored in electrically erasable programmable
read only memory (EEPROM) that retains the memory even when power to the TCU is disconnected. In operation the software continuously monitors the input values and uses these, via the shift schedule, to determine the required gear state, At the same time it monitors, via the solenoid outputs, the current gear state. Whenever the
input conditions change such that the required gear state is different to the current gear state, the TCU initiates a
gear shift to bring the two states back into line.
Once the TCU has determined the type of gear shift required the software accesses the shift logic, estimates the
engine torque output, adjusts the variable pressure solenoid ramp pressure then executes the shift.
The TCU continuously monitors every input and output circuit for short or open circuits and operating range. When
a failure or abnormal operation is detected the TCU records the condition code in the diagnostics memory and
implements a limp mode, The actual limp mode used depends upon the failure detected with the object to maintain
maximum driveability without damaging the transmission. In general input failures are handled by providing a default
value. Output failures, which are capable of damaging the transmission, result in full limp mode giving only third or
fourth gear and reverse. For further details of limp modes and memory retention refer to the Diagnostic Section.
The TCU is designed to operate at ambient temperatures between -40 and 85°C . It is also protected against
electrical noise and voltage spikes, however all the usual precautions should be observed, for example when arc welding or jump starting. TCU Inputs
To function correctly, the TCU requires engine speed, road speed, transmission sump temperature, throttle position
and gear position inputs to determine the variable pressure solenoid current ramp and on/off solenoid states. This
ensures the correct gear selection and shift feel for all driving conditions. The inputs required by the TCU are as follows: Engine Speed
The engine speed signal is derived from the tachometer signal line, a dedicated sensor or a Controlled Area Network (CAN).
Road Speed
4WD (Diesel) - The shaft speed signal is derived from the speedo sensor located on the transfer case. This signal is transmitted directly to the TCU.
4WD (Gasoline) - The speedo sensor sends the shaft speed signal to the engine control module (ECM). The
information is then transferred to the TCU via the CAN.
Transmission Sump Temperature
The transmission sump temperature sensor is a thermistor located in the solenoid wiring loom within the transmission.
This sensor is a typical NTC resistor with low temperatures producing a high resistance and high temperatures

5A-30 AUTOMATIC TRANSMISSION
Solenoid Valve Symbols (On/off Solenoids)
The solenoid symbol shown adjacent to each solenoid on the
hydraulic system schematics indicates the state of the oil flow
through the solenoid valve with the power On or 0ff. Refer to
figure 3.6 for the On/off operational details of NO solenoidvalves. Normally Open (NO) Solenoid POWER ON
Line 500 port is closed. The output port is open to exhaust at the solenoid valve. POWER OFF
The exhaust port is closed. The output port is open to line 500,Figure 3.6- Normally Open (NO) Symbols
Variable Pressure Solenoid Multiplexing System
Friction element shifting pressures are controlled by the variable pressure solenoid (VPS).
Line pressure is completely independent of shift pressure and is a function of throttle position, gear state and enginespeed.
S5 is a proportional or variable pressure solenoid that provides the signal pressure to the clutch and band regulator
valves thereby controlling shift pressures.
VPS pressure is multiplexed to the clutch regulator valve, the band regulator valve and the converter clutch regulator
valve during automatic gearshifts.
A variable pressure solenoid produces a hydraulic pressure inversely proportional to the current applied. During a
gearshift the TCU applies a progressively increasing or decreasing (ramped) current to the solenoid. Current applied will vary between a minimum of 200 mA and a maximum of 1000 mA, Increasing current decreases output (55)
pressure. Decreasing current increases output (55) pressure.
Line 500 pressure, (approximately 440 to 560 kPa), is the reference pressure for the VPS, and the VPS outputpressure is always below line 500 pressure.
When the VPS is at standby, that is no gearshift is taking place, the VPS current is set to 200 mA giving maximum output pressure.
Under steady state conditions the band and clutch regulator valve solenoids are switched off. This applies full Line
500 pressure to the plunger and because Line 500 pressure is always greater than S5 pressure it squeezes the S5
oil out between the regulator valve and the plunger. The friction elements are then fed oil pressure equal to Line 500multiplied by the amplification ratio.
When a shift is initiated the required On/off solenoid is switched on cutting the supply of Line 500 to the plunger.
At the same time the VPS pressure is reduced to the ramp start value and assumes control of the regulator valve by
pushing the plunger away from the valve. The VPS then carries out the required pressure ramp and the timed shift is
completed by switching Off the On/off solenoid and returning the VPS to the standby pressure.
This system enables either the band or clutch or both to be electrically controlled for each gearshift. Mode Indicator Light
Depending on the application, the mode indicator light may be used to indicate the mode that has been selected or
if an overheat condition exists. The mode indicator light is usually located on the instrument cluster. Communication Systems CAN
The controller area network (CAN) connects various control modules by using a twisted pair of wires, to share
common information. This results in a reduction of sensors and wiring. Typical applications include using the engine
controller to obtain the actual engine speed and throttle position, and adding these to the network. The ABS controller
(if fitted) can be used to obtain the road speed signal. This information is then available to the TCU without anyadditional sensors.

5A-36 AUTOMATIC TRANSMISSION
4-3 Sequence Valve
The 4-3 sequence valve (refer figure 3.14) is a two position spring loaded valve. It switches during 3-4 and 4-3
gearshifts although it performs no function during the 3-4 shift.
During the 4-3 shift the 4-3 sequence valve delays the connection of the clutch apply feed circuit (CAF) to the BIR
circuit until the BIR circuit has been fully pressurised by using the third gear circuit. This prevents objectionable
engine flare on completion of the 4-3 gearshift.
Figure 3.14 - 4-3 Sequence Valve
Figure 3.15 - Solenoid Supply Pressure Regulator Valve and Line Pressure Control Valve
Solenoid Supply Pressure Regulator Valve
The solenoid supply valve (refer figure 3.15) supplies a constant pressure to all solenoids (51 to 57). Line pressure
is used as the feed oil to this regulator and the output is termed line 500.
Line Pressure Boost Valve
Line pressure is controlled by 56, which acts as the line pressure boost valve (refer figure 3.15). When 56 pressure
is applied to the end of the PRV it is opposed by spring force and causes LOW line pressure for light throttleapplication and cruising.
Heavy throttle application causes the normally open 56 to open (switch Off) thus closing line 500 and opening 56 to
exhaust. Removal of 56 pressure from the PRV results in HIGH line pressure.

AUTOMATIC TRANSMISSION 5A-39
Primary Regulator Valve
The primary regulator valve (PRV) (refer to figure 3.19) regulates the transmission line pressure (or pump output
pressure). This valve gives either high or low line pressure depending on whether S6 is switched Off or On, When S6
is switched On,S6 pressure is applied to the PRV moving it against spring pressure and opening the line pressure
circuit to the pump suction port resulting in reduced line pressure. Low line pressure is used during light throttle
applications and cruising. Heavy throttle will cause S6 to switch Off and thereby cause high line pressure.
This stepped line pressure control has no detrimental effect on shift feel because all shifting pressures are controlled
by separate band and clutch regulator valves, and the output of S5.
When reverse gear is selected, both the low and high line pressure values are boosted to guard against slippage.
This is achieved by applying reverse oil line pressure to the PRV to assist the spring load. The other end of the valvecontains ports for line pressure feedback and 56 pressure.
The PRV also regulates the supply of oil to the converter via the converter feed port. The cascade effect of the PRV
ensures the first priority of the valve is to maintain line pressure at very low engine speeds. When the engine speed
increases and the pump supplies an excess of oil the PRV moves to uncover the converter feed port thereby pressurising
the converter. If there is an excess of oil for the transmission’s needs then the PRV moves further to allow oil to return
to the suction port.
Figure 3.19 - Primary Regulator Valve

5A-74 AUTOMATIC TRANSMISSION
Action
Inspect, repair C2 and adjust the linkage as neces-
sary. Repair C2. Inspect, repair or replace S6 as neces-
sary.Repair C2. Inspect, replace the sealing rings and/
or shaft as necessary. Repair C2. Inspect, repair or replace the C2 piston
as necessary.
Inspect C4 and repair as necessary.Inspect and adjust the C4 pack clearance as nec-
essary. Repair C4. Inspect and replace the wave plate as
necessary.Repair C4. Inspect and realign the wave plate as
necessary.Repair C4. Inspect and realign the sealing rings
and/or shaft as necessary. Repair C4. Inspect and refit the OWC as neces-
sary.Repair C4. Inspect and replace the C2 piston as
necessary.
Repair C4. Inspect and refit the ball as necessary.Inspect and repair B1 and replace the spring as
necessary.Replace sealing ring.
Repair B1. Refit the ball as necessary. Inspect and repair C1 and replace the spring.Repair C1. Inspect and replace the sealing tongs
and/or shaft as necessary.Repair C1. Inspect and replace the C1 piston as
necessary. Repair C1. Inspect and refit the capsule as neces-
sary.Repair C1. Inspect and refit the valve as neces-
sary. Repair C1. Inspect and replace the ball as neces-
sary.
Inspect and adjust the band as necessary.
Inspect and refit the ball as necessary.Inspect and replace the ‘O’ ring as necessary.
Inspect and refit the valve as necessary.Inspect and replace the ‘O’ ring as necessary.
Inspect and refit the valve as necessary.
Possible Cause
T-bar linkage out of adjustment.
56 foiled - stuck low. Overdrive/output shaft sealing rings damaged. C2 piston cracked. Incorrect C4 pack clearance. C4 wave plate broken.
C4 wave plate not lined up properly.Overdrive or output shaft sealing rings dam- aged. 3-4 one way clutch (OWC) in backwards. C2 piston cracked. Over-run clutch (OC)/low-1st ball misplaced. B1R spring broken. Input shaft sealing ring cut. C1/B1R ball misplaced. B1R spring left out.Overdrive or input shaft sealing rings damaged. C1 piston cracked. Ball capsule jammed. 4-3 sequence valve in backwards. Clutch apply feed (CAF)/B1R ball left out. Rear band incorrectly adjusted or damaged. Reverse-low/first ball misplaced.Input shaft ‘O’ ring missing or damaged.
Converter clutch regulator valve in backwards.Input shaft ‘O’ ring missing or damaged.
C1 bias valve in backwards.
Symptom
C2 burnt C4 burnt B1 burnt C1 burnt Slips in reverse - no manual 1st Firm converter
lock or unlockNo lock up at lightthrottle
Table 6.2.4 - After Teardown Faults

5A-80 AUTOMATIC TRANSMISSION6. Switch off the engine and raise the vehicle on the hoist, if applicable, ensuring that the vehicle is level.
7. Three minutes after the engine has stopped, but no longer than one hour, remove the filler pump, The correct level is reached when ATF is aligned with the bottom of the filler hole. If the correct level is not reached, then add
a small quantity of ATF to the correct level.
8. Replace the transmission filler plug and clean all remnants of ATF on the transmission and vehicle.
9. Tighten the transmission filler plug to specification.
Checking, Adding Fluid and Filling - Drained or Dry Transmission
To set the correct fluid level proceed as follows. 1. Set the transmission selector to Park and switch the engine off.
2. Raise the vehicle on a hoist (or leave over a service pit).
3. Clean all dirt from around the service fill plug prior to removing the plug, Remove the oil service fill plug. Clean the fill plug and check that there is no damage to the ‘O’ ring. Install the filler pump into the filler hole.
4. Lower the vehicle with the filler pump still connected and partially fill the transmission. This typically requires approximately :
a. If the transmission torque converter is empty:
9.0 litres - 4WD9.0 litres - RWD
b. If the transmission torque converter is full: 4.5 litres - 4WD4.5 litres - RWD
5. Start the vehicle in Park with the Parking brake and foot brake applied with the engine idling, cycle the transmission gear selector through all positions, adding ATF until gear application is felt.
6. Then add an additional 0.5 litres of ATF.
7. Switch off the engine and raise the vehicle on the hoist. Remove the filler pump and replace the filler plug. The plug shall be tightened to specification.
8. The vehicle is then to be driven between 3.5 and 4.5 kilometers at light throttle so that the engine does not exceed 2500 rpm. This should result in the transmission temperature being in the range 50 to 60 °C.
9. With the engine idling, cycle the transmission selector through all gear positions with the brake applied.
10. Stop the engine. Raise the vehicle on the hoist, if applicable ensuring the vehicle is level.
11. Three minutes after the engine has stopped, but no longer than one hour, remove the filler plug. The correct level is reached when ATF is aligned with the bottom of the filler hole. If the correct level is not reached, then add
a small quantity of ATP to the correct level.
12. Replace the transmission filler plug and clean all remnants of ATF on the transmission and vehicle. Tighten the transmission Filler plug to specification.
ELECTRONIC ADJUSTMENTS Idle Speed Adjustment
Carry out the adjustments to the idle speed as detailed in the workshop manual.
Throttle Position Calibration
Should the throttle position data stored in the TCU be lost or be out of specification, as indicated by a diagnostic
trouble message, it may be re-established by the following procedure. Check that the hot engine idle speed is within specification.
Allow the engine to idle in ‘Drive ’ for 60 seconds with the air conditioner (if fitted) turned off. The closed throttle
reference point in the TCU has now been set.
Switch the engine off but leave the ignition on. Hold the accelerator pedal on the floor for 60 seconds. The wide open
throttle reference point in the TCU has now been set.

5B-34 MANUAL TRANSMISSION
COUNTER SHAFT Disassembly Procedure
1. Using a hydraulic press and special tool, remove the frontbearing assembly from the counter shaft.
2. Check and clean all removed parts and replace if necessary. Assembly Procedure
1. Using a hydraulic press and installer, press the front bearing assembly onto the counter shaft.
2. Install is as follows : Install a new O-ring on the counter shaft outer race and
lubricate it.
Using a installer, lightly tap the race into its bore until the
O-ring is compressed.
Install the race to be fully seated on the inside of the
case.

5D1-4 TRANSFER CASE (PART TIME 4408)SELF-DIAGNOSIS
SYSTEM DESCRIPTION
1. TCCU detects transfer case system malfunctions and indicates malfunctioning part(s) through flashing 4H,4L indicator lights.
Using a service connector, connect it to the diagnosis box in the engine room and read the flashing of the ‘4WD
CHECK ’ indicator light.
The flashing indicator light will show you defective code(s).
2. Identify 7 defective codes after reading the flashing indicator light.
TCCU
Shift motor
Magnetic synchronizer clutch
Speed sensor
Hub solenoid
Selector switch
Motor position sensor
3. Transfer case system is malfunctioning when: 4H ,4L indicator lights are remain on after 0.6 second when turning the ignition switch ‘ON ’
4H,4L indicator lights are continuously come on during driving.
4. If only 1 part is malfunctioning, ‘4WD CHECK ’ indicator light
will display defective code 3 times continuously.
5. If more then 2 part is malfunctioning, the first malfunctioning part will be displayed 3 times and following malfunctioningparts will be displayed .
6. To read defective code, connect the service connector and turn the ignition switch 'ON'.
7. After repairing, eliminate the defective code stored in the TCCU. NoticeBefore replacing the malfunction parts with defective code, check the wires and connectors for proper condition.