1998 SSANGYONG MUSSO 4WD

GENERAL INFORMATION 0B-3
662LA
MB
W4A040
3.871
2.247
1.436
1.000
5.586
5.38
9 - 9.5
Auto Transmission (MB)
Application
Maker
Type or Model
Gear Ratio : 1st
2nd
3rd
4th
Reverse
Final Drive Ratio
Oil Capacity (L)2.3L DOHC
MB
W4A040
3.871
2.247
1.436
1.000
5.586
4.27
9 - 9.53.2L DOHC
MB
W4A040
3.871
2.247
1.436
1.000
5.586
3.73
9 - 9.5
661LA
BTRA
M74 4WD
2.741
1.508
1.000
0.708
2.429
5.38
9
Auto Transmission (BTRA)
Application
Maker
Type or Model
Gear Ratio : 1st
2nd
3rd
4th
Reverse
Final Drive Ratio
Oil Capacity (L)662LA
BTRA
M74 4WD
2.741
1.508
1.000
0.708
2.429
4.89
92.3L DOHC
BTRA
M74 4WD
2.741
1.508
1.000
0.708
2.429
5.86
93.2L DOHC
BTRA
M74 4WD
2.741
1.508
1.000
0.708
2.429
4.89
9
Tire and Wheel
Specifications
P235/75 R15, 255/70 R15
7JJ ´ 15
30 Psi
30 Psi
30 Psi
30 Psi Application
Standard Tire Size
Standard Wheel Size
Inflation Pressure At Full Lode
P235 / 75 : Front
Rear
P255 / 75 : Front
Rear Application
Booster Size
Master Cylinder Diameter (mm)
Booster Ratio
Front Brake : Disc Type
Rear Brake : Disc Type
Specifications
8inch + 9inch
7inch + 8inch
8inch + 9inch
f 25.4
5.6 : 1
Ventilated
Solid
Brake
non-ABS
ABS 5.0
ABS 5.3

AUTOMATIC TRANSMISSION 5A-5
SCHEMATIC AND ROUTING DIAGRAMS
TCU CIRCUIT (4WD-DIESEL)

5A-6 AUTOMATIC TRANSMISSION
TCU CIRCUIT (4WD-GASOLINE)

5A-18 AUTOMATIC TRANSMISSION
INTRODUCTION
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)
320Configuration
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

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:
lProcessing logic circuits which include a central microcontroller and a back-up memory system.
lInput circuits.
lOutput 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:
lEngine Speed
The engine speed signal is derived from the tachometer signal line, a dedicated sensor or a Controlled Area
Network (CAN).
lRoad 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.
lTransmission 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-48 AUTOMATIC TRANSMISSION
POWER FLOW - PARK AND NEUTRAL
In Park and Neutral, there is no drive to the planetary gear set. The rear band is applied to eliminate ‘clunk’ on
engagement of the reverse gear, and to improve the low range engagement for 4WD applications. No other clutches
or bands are applied.
In Park the transmission is mechanically locked by engaging a case mounted pawl with teeth on the output shaft ring
gear.
Control
To maintain this arrangement in the steady state solenoids and valves are activated as follows:
lSolenoids S1 and S2 are switched off.
lLine (pump) pressure is applied to the primary regulator valve (PRV) and to the solenoid supply valve.
lThe converter, oil cooler, and lubrication circuits are charged from the primary regulator valve.
lThe line 500 circuit is charged by the solenoid supply valve.
lThe S5 circuit is charged by the variable pressure solenoid (S5).
lLine pressure is prevented from entering the drive circuit by the manual valve.
lThe B1 circuit and all clutch circuits are open to exhaust.
Refer to figure 5.1 and table 5.2.
Table 5.2 - Engaged Elements - Park arid Neutral
Gear State
Park and NeutralC1
-C2
-C3
-C4
-B1
-B2
X1-2
OWC
-3-4
OWC
-LU
CLUTCH
- ELEMENTS ENGAGED

5A-60 AUTOMATIC TRANSMISSION
DIAGNOSIS
DIAGNOSTIC SYSTEM
Recommended Test Equipment and Procedure
The test equipment is designed to be used with the control modules in all vehicles. The components used in the
transmission application are:
lMulti Function Tester, and
lAppropriate vehicle for testing.
Multi Function Tester (MFT)
The MFT is programmed with the special vehicle diagnostic software that allows selection of the unit under test.
The program allows the proper communication to the Transmission Control Unit (TCU).
It then requests information from the user via a menu system to select the required set up.
Examples are viewing codes, clearing error codes, and real-time operation. Set up and operation instructions are
detailed in the user manual.
This equipment can be used by trained personnel such as technicians and mechanics to diagnose electronic and
wiring problems relating to the vehicle transmission. Information that is available includes engine and road (shaft)
speed, transmission oil temperature, throttle position, solenoid/gear status and gear lever position. Current and
stored faults detected by the electronics are also available.
TCU Pin Description
The TCU pin descriptions are listed in table 6.1.1.
The wiring loom pins are shown in figure 6.1.1
Pin
No.
1
2
3
4
5
6
7
8Identification
Common Ground
Do not use
Mode Indicator Lamp -
‘Winter’
Gear Position ‘Park’
Lamp
Gear Position ‘Reverse’
Lamp
Gear Position ‘Neutral’
Lamp
Do not use
Engine Speed Input
Sensor (-Ve)Type
GND
-
OP
OP
OP
OP
-
IPDescription
Main power ground (or the module. Connects
directly to the battery negative terminal.
Indicates ‘WINTER’ mode shift schedule is se-
lected.
Drives the jewel in the instrument cluster to in-
dicate ‘PARK’ gear lever position.
Drives the jewel in the instrument cluster to in-
dicate ‘REVERSE’ gear lever position.
Drives the jewel in the instrument cluster to in-
dicate ‘NEUTRAL’ gear lever position.
Flywheel/Ring gear pulses to indicate engine
speed. 4WD
(Diesel)
O
O
l
l l l
l
4WD
(Gas)
O
O
O
l
l l l
l
l
Table 6.1.1 - TCU Pin Description

AUTOMATIC TRANSMISSION 5A-61
Pin
No.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30Identification
Mode Indicator Lamp -
‘Power’
Throttle Position Sensor
Output as Pulse Width
Modulation for TOD
Air Conditioner Input Signal
Kickdown Switch
Mode Switch
Transfer Case Input
(High) -4WD Lamp High
Ignition Switch
Do not use
Gear Position ‘1’ Lamp/
Gear Position Code 1
*Gear Position ‘2’ Lamp/
Gear Position Code 2*
Gear Position ‘3’ Lamp/
Gear Position Code 3*
Gear Position ‘Drive’
Lamp/
Gear Position Code 4*
CAN (-ve)
CAN (+ve)
K-line Communication Link
Engine Speed Input
Sensor (+ve)
Road Speed Pulses
Shaft Speed Sensor
Signal
Throttle Position Sensor -
Ground
Throttle Position Sensor -
Reference
Throttle Position Sensor -
Input Signal
Transfer(or Case Input
(Low) - 4WD Lamp LowType
OP
OP
-
IP
IP
IP
IP
-
OP
OP
OP
OP
I/O
I/O
I/O
IP
OP
IP
GND
REF
IP
IPDescription
Indicates ‘POWER’ mode shift schedule is se-
lected.
Provides an analogue signal of the throttle po-
sition for the Torque on Demand (TOD) Con-
trol Module.
Input
Switch to indicate when a kickdown is required
at high throttle position.
Switch to select ‘NORMAL’, ‘POWER’ or ‘WIN-
TER’ shift schedule.
Voltage varies from OV to 12V.
Switch to indicate 4WD’HIGH RANGE’ is se-
lected.
Ignition power is used as the main power source
to drive the unit and the solenoids.
Drives jewel in the instrument cluster to indi-
cate
gear leverposition’1'. Drives jewel in the instru-
ment cluster to indicate
gear lever position’2'. Drives jewel in the instru-
ment cluster to indicate gear lever position’3'.
Drives jewel in the instrument cluster to indi-
cate
‘DRIVE’. gear lever position.
CAN low side bus communication (CANL).
CAN high side bus communication (CANH).
Diagnostic information and vehicle coding.
Flywheel/Ring gear pulses to indicate engine
speed.
Road speed signals derived from shaft speed
sensors.
This sensor transmit shaft speed signal to the
TCU.
Throttle position sensor ground.
This is the 5V reference voltage supply gener-
ated by the unit for the throttle position sensor.
This sensor is a resistance potentiometer indi-
cating throttle position.
Voltage varies 0V to 5V.
Switch to indicate 4WD’LOW RANGE’ is se-
lected. 4WD
(Diesel)
O
O
O
O
l
l
l
4WD
(Gas)
O
O
O
O
O
O
O
O
l
l
l
ll
ll
ll
ll
ll
ll
l
l
ll
l
ll
l
l
l
l
ll l