1998 SSANGYONG MUSSO lock

5A-22 AUTOMATIC TRANSMISSION
CONTROL SYSTEMS
GENERAL
There are two control systems associated with the transmission. The electronic control system monitors vehicle
parameters and adjusts the transmission performance. The hydraulic control system implements the electronic control
system commands.
ELECTRONIC CONTROL SYSTEM
The electronic control system is comprised of sensors, a TCU and seven solenoids. The TCU reads the inputs, and
under software control activates the outputs according to values stored in read only memory (ROM).
The TCU controls the hydraulic control system. This control is via the hydraulic valve body, which contains seven
electro-magnetic solenoids. Six of the seven solenoids are used to control the line pressure, operate the shift valves
and the torque converter lock-up clutch, and to turn on and off the two regulator valves (The two regulator valves
control the shift feel.).
The seventh solenoid is the proportional or variable pressure solenoid (VPS) which works with the two regulator
valves to control shift feel.
Figure 3.1 details a typical TCU control system schematic.
The individual component locations, operation and specifications which make up the electronic control subsystem
are covered in this section.
Figure 3.1 - Typical TCU Control System Schematic

AUTOMATIC TRANSMISSION 5A-25
producing a low resistance.
Temperature/Resistance characteristics and location within the solenoid wiring loom are given in tables 3-1 and 3-
2, and figures 3.2 and 3.3.
If the transmission sump temperature exceeds 135°C, the TCU will impose converter lock-up at lower vehicle
speeds and in some vehicles flashes the mode indicator lamp. This results in maximum oil flow through the
external oil cooler and eliminates slippage in the torque converter. Both these actions combine to reduce the oil
temperature in the transmission.
Connects To
Solenoid 1
Solenoid 2
Solenoid 3
Solenoid 4
Solenoid 5
Solenoid 6
Solenoid 7
Solenoid 5
Temp Sensor
Temp SensorWire Color
Red
Blue
Yellow
Orange
Green
Violet
Brown
Green
White
WhitePin No.
1
2
3
4
5
6
7
8
9
10
Table 3.2 - Pin No. Codes for Temperature Sensor Location In Solenoid Loom
Figure 3.3 - Temperature Sensor Location in Solenoid Loom

AUTOMATIC TRANSMISSION 5A-31
K-Line
The K-line is typically used for obtaining diagnostic information from the TCU. A computer with a special interface is
connected to the TCU and all current faults, stored faults, runtime parameters are then available. The stored fault
codes can also be cleared.
The K-line can be used for vehicle coding at the manufacturer’s plant or in the workshop. This allows for one TCU
design to be used over different vehicle models. The particular code is sent to the microprocessor via the K line and
this results in the software selecting the correct shift and VPS ramp parameters.
HYDRAULIC CONTROL SYSTEM
The hydraulic controls are located in the valve body, pump body and main case.
The valve body contains the following:
lManual valve,
lThree shift valves,
lSequence valve,
lsolenoid supply pressure regulator valve,
lline pressure control valve,
lclutch apply regulator valve,
lband apply regulator valve,
lS1 to S6, and
lReverse lockout valve.
lThe pump body contains the following:
lPrimary regulator valve for line pressure,
lconverter clutch regulator valve,
lconverter clutch control valve,
lS7,and
lC1 bias valve.
The main case contains the following:
lB1R exhaust valve
The hydraulic control system schematic is shown at figure 3.7.
All upshifts are accomplished by simultaneously switching on a shift valve(s), switching VPS pressure to the band
and/or clutch regulator valve, and then sending the VPS a ramped current. The shift is completed by switching the
regulators off and at the same time causing the VPS to reach maximum . pressure. All downshifts are accomplished
by switching VPS pressure to the band and/or clutch regulator valve and sending a ramped current to the VPS. The
shift is completed by simultaneously switching the regulators off, switching the shift valves and at the same time
causing the VPS to return to stand-by pressure.
The primary regulator valve is located in the pump cover and supplies four line pressures; high and low for forward
gears, and high and low for reverse. This pressure has no effect on shift quality and merely provides static clutch
capacity during steady state operation. Low pressure can be obtained by activating an On/off solenoid with high line
pressure being the default mode.
Torque converter lock-up is initiated by toggling the converter clutch control valve with an On/off solenoid. The actual
apply and release of the clutch is regulated by the VPS via the converter clutch regulator valve. As an additional
safety feature, the lock-up is hydraulically disabled in first and second gear by the bias valve which only supplies oil
to the lock-up solenoid when C1 is applied in third and fourth gears. This prevents the vehicle from being rendered
immobile in the unlikely event of S7 becoming stuck.
The solenoid supply valve provides reference pressure for all the solenoids.

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 the
forward 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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AUTOMATIC TRANSMISSION 5A-41
C1 Bias Valve
The C1 bias valve (refer figure 3.22) ensures that the converter lock-up clutch is only applied in third and fourth
gears. It uses C1 clutch oil pressure as the switching signal since C1 is only applied in third and fourth gears.
Line to 500 oil is routed through the C1 bias valve to S7. The C1 bias valve therefore acts as a safety feature to
ensure drivability in the event of S7 failure.
Figure 3.22- C1 Bias Valve
B1R Exhaust Valve
The B1R exhaust valve (refer figure 3.23) is a two position
spring loaded valve located in the transmission case directly
adjacent to the front servo. It permits the servo release oil to
be rapidly exhausted into the transmission case during
application of the front band (B1). This prevents the need to
force the oil back from the front servo through the valve body
and through the 3-4 shift valve. The spring positions the valve
to prevent oil entering the release area of the servo until the
B1R circuit oil pressure reaches approximately 100 kPa.
Figure 3.23 - B1R Exhaust Valve

5A-42 AUTOMATIC TRANSMISSION
POWER TRAIN SYSTEM
The Power Train System consists of:
lA torque converter with single face lock-up clutch
lFour multi-plate clutch assemblies
lTwo brake bands
lTwo one-way clutches
lPlanetary gearset
lParking mechanism
A conventional six pinion Ravigneaux compound planetary gearset is used with overdrive (fourth gear) being obtained
by driving the carrier.
The cross-sectional arrangement is very modular in nature. Four main sub-assemblies are installed within the case
to complete the build. These sub-assemblies are:
lGearset-sprag-centre support
lC1 -C2-C3-C4 clutch sub-assembly
lPump assembly
lValve body assembly
One, or a combination of selective washers are used between the input shaft flange and the number 4 bearing to
control the transmission end float. This arrangement allows for extensive subassembly testing and simplistic final
assembly during production.
A general description of the operation of the Power Train System is detailed below. Refer to table 4.1 and figure 4.1.
First gear is engaged by applying the C2 clutch and locking the 1-2 One Way Clutch (1-2 OWC). The 1-2 shift is
accomplished by applying the B1 band and overrunning the 1-2 OWC. The 2-3 shift is accomplished by applying the
C1 clutch and releasing the B1 band. The 3-4 shift is accomplished by re-applying the B1 band and overrunning the
3-4 OWC. Reverse gear is engaged by applying the C3 clutch and the B2 band.
The C4 clutch is applied in the Manual 1,2 and 3 ranges to provide engine braking. In addition, the C4 clutch is also
applied in the Drive range for second and third gears to eliminate objectionable freewheel coasting. The B2 band is
also applied in the Manual 1 range to accomplish the low-overrun shift.
Both the front and rear servos are dual area designs to allow accurate friction element matching without the need for
secondary regulator valves. All the friction elements have been designed to provide low shift energies and high static
capacities when used with the new low static co-efficient transmission fluids. Non-asbestos friction materials are used
throughout.
Gear
First
Second
Third
Fourth
Reverse
Manual 1Gear
Ratio
2.741
1.508
1.000
0.708
2.428
2.741C1
X
XC2
X
X
X
X
XC3
XC4
X
XB1
X
X
XB2
X
X1-2
OWC
X3-4
OWC
X
X
XLU
CLUTCH
X*
X ELEMENTS ENGAGED
* For Certain Vehicle Applications, Refer to the Owner's Manual. Table 4.1 - Engaged Elements vs Gear Ratios

AUTOMATIC TRANSMISSION 5A-43
Figure 4.1 - Power Flow Diagram
TORQUE CONVERTER
The torque converter (refer figure 4.2) consists of a turbine,
stator pump, impeller and a lock-up damper and piston
assembly. As in conventional torque converters, the impeller is
attached to the converter cover, the turbine is splined to the
input shaft and the stator is mounted on the pump housing via
a one way clutch (sprag).
The addition of the damper and piston assembly enables the
torque converter to ‘lock-up’ under favourable conditions. Lock-
up is only permitted to occur in third and fourth gears under
specified throttle and road speed conditions.
Lock-up is achieved by applying hydraulic pressure to the
damper and piston assembly which couples the turbine to the
converter cover, locking-up the converter and eliminating
unwanted slippage. Whenever lock-up occurs, improved fuel
consumption is achieved. Torsional damper springs are
provided in the damper and piston assembly to absorb any
engine torque fluctuations during lock-up.
Figure 4.2 - Torque Converter Cross Section

AUTOMATIC TRANSMISSION 5A-45
BANDS
The transmission utilises two bands, the B1 band (sometimes known as the 24 band), and the B2 band (sometimes
known as the low-reverse band). Refer to figure 4.4.
The B1 band is a flexible band which is engaged by the front servo piston. B1 is activated in second and fourth gear.
When activated B1 prevents the reverse sun gear from rotating by holding the C3 clutch assembly stationary. In
second gear only the outer area of the apply piston is utilised. In fourth gear both areas are utilised for greater
clamping force.
The B2 band is a solid band which is engaged by the rear servo piston. B2 is activated in Park,
Reverse, Neutral and Manual 1. When activated B2 prevents the planet carrier assembly from rotating. In Manual 1
only the inner area of the apply piston is utilised. In Park, Reverse and Neutral, both areas are utilised for greater
clamping force.
Figure 4.4- Bands
ONE WAY CLUTCHES
The transmission uses two OWCs, the 1-2 OWC and the 34 OWC. (Note that a third OWC is located in the torque
converter, also known as a sprag.)
The 1-2 OWC is located between the planetary carrier assembly and the centre support. This allows the carrier to
rotate around the centre support in one direction only. The one way clutch is engaged only in Drive 1.
The 3-4 OWC is located between the C4 and the C2 clutch assemblies. This allows the C2 clutch to drive the forward
sun gear in first, second and third gears but unlocks in fourth gear and during overrun.
PLANETARY GEAR SET
The planetary gear set used in the transmission is a conventional six pinion Ravigneaux compound gear set.