2003 SSANGYONG MUSSO engine

5A-2 AUTOMATIC TRANSMISSIONSPECIFICATIONS
MODEL PART NUMBERS AND APPLICATIONS
Transmission
0574-000001 (9) 0574-000002 (8)
0574-000004 (10) 0574-000005 (7) Torque Converter
179K160K160K179KEngine Version661LAE32
662LA(Turbo) E23
MODEL SPECIFICATIONS
Application
Torque Converter Mean diameter of fluid circuit Maximum torque multiplication Stall speed (rpm)0574-000001 (D23LA)0574-000002 (E32)0574-000004 (D29LA) 0574-000005 (E23) 0574-0000200574-000021
Gear Ratios First Second ThirdFourthReverse
Lubricant
TypeCapacityDry SystemService Refill
Gear Train End Float Gear Set Pinion End FloatDescriprtion
260
2.0 : 1
2100 - 2250 2050 - 22502100 - 2200 1800 - 2100
2.741 : 1 1.508 : 11.000 : 10.708 : 12.429 : 1
Castrol TQ95 or other approved fluid 9.0 Litres (approx)4.5 Litres (approx)0.50 - 0.65 mm0.10 - 0.50 mm
DWMC P/NO
36100-05420 (1)36100-05430 (1)36100-05410 (1)36100-05440 (1)

5A-18 AUTOMATIC TRANSMISSIONINTRODUCTION
The BTR Automotive Model 74 Four Speed Automatic Transmission is an electronically controlled overdrive four
speed unit with a lock-up torque converter. The lock-up torque converter results in lower engine speeds at cruise and
eliminates unnecessary slippage. These features benefit the customer through improved fuel economy and noise
reduction. Refer to table 1.1 for details of power, torque and configuration.
Of primary significance is the transmission control unit (TCU) which is a microprocessor based control system. The
TCU utilizes throttle position, rate of throttle opening, engine speed, transmission output speed, transmission sump
temperature, gear selector position and mode selector inputs, and in some applications a ‘kickdown’ switch to control
all shift feel and shift schedule aspects.
The TCU drives a single proportional solenoid multiplexed to three regulator valves to control all shift feel aspects.
The output pressure of this solenoid is controlled as a function of transmission sump temperature to maintain consistent
shift feel throughout the operating range.
Shift scheduling is highly flexible, and several independent schedules are programmed depending on the vehicle.
Typically the ‘NORMAL’ schedule is used to maximise fuel economy and driveability, and a ‘POWER’ schedule is used
to maximise performance. ‘WINTER’ schedule is used to facilitate starting at second gear.
Figure 1.1 details the differences between conventional and electronic transmission control systems.
Max Torque (Nm)
320 Configuration
260 mm Torque Converter Wide Ratio Gear Set
Splined Output for Transfer CaseMin Torque (Nm) 160
Model
M74 4WD
Transmission
Table 1.1 - M74 Torque, Power and Configuration

AUTOMATIC TRANSMISSION 5A-21
Downshift Type
RANGE ‘1’ (MANUAL ‘1’):
RANGE ‘2’ (MANUAL ‘2’):
RANGE ‘3’ (MANUAL ‘3’):
RANGE ‘D’ (DRIVE):
RANGE ‘N’ (NEUTRAL):
RANGE ‘R’ (REVERSE):
RANGE ‘P’ (P ARK):Inhibited Above
First gear operation only with inhibited engagement as a function of vehicle speed. Engine braking is applied with reduced throttle.
First and second gear operation with inhibited engagement of second gear, as
a function of vehicle speed. Engine braking is applied with reduced throttle.
First, second and third gear operation with an inhibited third gear engagement
at high vehicle speed. Refer to the vehicle owner’ s manual.Engine braking is applied with reduced throttle.
First, second, third and fourth gear operation. First to second (1-2), first to third
(1-3), second to third (2-3), second to fourth (2-4), third to fourth (3-4), fourth
to third (4-3), fourth to second (4-2), third to second (3-2), third to first (3-1)
and second to first (2-1), shifts are all available as a function of vehicle speed,throttle position and the time rate of change of the throttle position (forced
downshift). Lockup clutch may be enabled in 3rd and 4th gears depending on
vehicle type. Refer to the owner’ s manual.
Rear band applied only, with inhibited engagement as a function of vehicle
speed, engine speed and throttle position. The inhibitor switch allows the en-gine to start.
Reverse gear operation, with inhibitor engagement as a function of vehicle
speed, engine speed and throttle position. The inhibitor switch enables reverse lamp operation.
Rear band applied only, with inhibited engagement as a function of vehicle
speed, engine speed and throttle position. The transmission output shaft is
locked. The inhibitor switch allows the engine to start.
Table 2.1 - Gear Selections DRIVING MODE SELECTOR
The driving mode selector consists of a mode selection switch and indicator light. The driving mode selector is
located on the centre console. See figure 2,1.
The schedules available to be selected vary with vehicle types. Typically the driver should have the option to select
between ‘NORMAL’ , ‘POWER’ or ‘WINTER’ modes.
When ‘NORMAL’ mode is selected upshifts will occur to maximise fuel economy and the indicator lights remain
extinguished. When ‘POWER’ mode is selected upshifts will occur to give maximum performance and the ‘POWER’
mode indicator light is swi tched on. When ‘WINTER’ mode is selected, starting at second gear is facilitated, the
‘WINTER’ mode indicator light is switched on and the ‘POWER’ mode indicator light is switched off.
Refer to the vehicle owner ’ s manual for specific modes for each vehicle type.

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-26 AUTOMATIC TRANSMISSIONInhibitor Switch
Throttle Position SensorThe throttle position sensor(TPS) is a resistance potentiometer mounted on the throttle body of the engine.
It transmits a signal to the TCU proportional to the throttle plate opening. The potentiometer is connected to the TCU by three wires:
5 volts positive supply, earth and variable wiper voltage.Throttle voltage adjustments are as follows:
Closed throttle voltage is 0.2V to 1.0V.
Wide open throttle voltage is 3V -4.7V.
These measurements are taken between pins 29 and 27 of the TCU.
Maintaining good shift feel through the transmission life span is dependant on having an accurate measure of
the engine throttle position. To achieve this the TCU
continuously monitors the maximum and minimum throttle
potentiometer voltages and, if a change occurs, stores the new voltage values.
However these limits will be lost and will require relearning
should a new TCU be installed, or the throttle calibration data
is cleared by the execution of a particular sequence, This last
instance depends on the installation, and reference should be
made to the Diagnostics Section of this manual. The relearningwill happen automatically Notice
Above figure of T.P.S. is for the diesel enginewhich is installed on the injection pump.
Gear Position Sensor
The gear position sensor is incorporated in the inhibitor switch mounted on the side of the transmission case.
(Refer to figure 3.5.) The gear position sensor is a multi-function switch providing three functions: Inhibit starting of the vehicle when the shift lever is in aposition other than Park or Neutral
Illuminate the reversing lamps when Reverse is
selected indicate to the TCU which lever position has been selected by way of a varying resistance (Refer to
table 3.3.)
Figure 3.5 - Inhibitor Switch

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.

5A-38 AUTOMATIC TRANSMISSION
Reverse Lockout Valve
The reverse lockout valve (refer figure 3.18) is a two position valve contained in the upper valve body. This valve
uses 51-52 pressure as a signal pressure and controls the application of the rear band (B2).
While the manual valve is in D,3,2, or 1 positions, drive oil is applied to the spring end of the valve, overriding any
signal pressures and holding the valve in the lockout position. This prevents the application of B2 in any of theforward driving gears.
When the manual valve is in P, R or N positions, drive oil is exhausted and the reverse lockout valve may be toggled by S1-S2 pressure.B2 is applied in P, R, and N provided that the following conditions are satisfied:
1. In P or N, roadspeed 3 km/h.
2. In R, road speed 10 km/h.
3. Engine speed 1400 rpm.
4. For diesel vehicles, throttle 25%.
5. For gasoline vehicles, throttle 12%.
Under these conditions, the TCU switches solenoids S1 and S2 to Off. The reverse lockout valve toggles under the
influence of the S1-S2 pressure, to connect the line pressure to the B2 feed. Oil is fed to both the inner and outer
apply areas of the rear servo piston, applying B2.
If any of the above conditions are not satisfied, the TCU switches solenoids S1 and S2 to On. S1- S2 pressure is
exhausted and the valve is held in the lockout position by the spring. In this position, engagement of B2 is prohibited.
This feature protects the transmission from abuse by preventing the undesirable application of B2 at high speed, and
by providing a reverse lockout function.
Note that if the transmission is in failure mode, the rear band will be applied at all times in P, R and N.
Figure 3.18 - Reverse Lockout Valve <
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