(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak. If a leak is
present in this area, remove transmission for further
inspection.
(a) Circular spray pattern generally indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, oil gallery cup
plug, bedplate to cylinder block mating surfaces
and seal bore. See proper repair procedures for
these items.
(4) If no leaks are detected, pressurize the crank-
case as previously described.
CAUTION: Do not exceed 20.6 kPa (3 psi).
(5) If the leak is not detected, very slowly turn the
crankshaft and watch for leakage. If a leak is
detected between the crankshaft and seal while
slowly turning the crankshaft, it is possible the
crankshaft seal surface is damaged. The seal area on
the crankshaft could have minor nicks or scratches
that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft
polishing is necessary to remove minor nicks and
scratches. The crankshaft seal flange is especially
machined to complement the function of the rear oil
seal.
(6) For bubbles that remain steady with shaft
rotation, no further inspection can be done until dis-
assembled.
(7) After the oil leak root cause and appropriate
corrective action have been identified, replace compo-
nent(s) as necessary.
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE TEST
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Check engine oil level and add oil if necessary.
(2) Drive the vehicle until engine reaches normal
operating temperature. Select a route free from traf-
fic and other forms of congestion, observe all traffic
laws, and accelerate through the gears several times
briskly.
(3) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for abnor-
mal firing indicators fouled, hot, oily, etc. Record cyl-
inder number of spark plug for future reference.(4) Remove the Auto Shutdown (ASD) relay from
the PDC.
(5) Be sure throttle blade is fully open during the
compression check.
(6) Insert compression gauge adaptor Special Tool
8116 or the equivalent, into the #1 spark plug hole in
cylinder head. Connect the 0±500 psi (Blue) pressure
transducer (Special Tool CH7059) with cable adap-
tors to the DRBIIIt. For Special Tool identification,
(Refer to 9 - ENGINE - SPECIAL TOOLS).
(7) Crank engine until maximum pressure is
reached on gauge. Record this pressure as #1 cylin-
der pressure.
(8) Repeat the previous step for all remaining cyl-
inders.
(9) Compression should not be less than 689 kPa
(100 psi) and not vary more than 25 percent from cyl-
inder to cylinder.
(10) If one or more cylinders have abnormally low
compression pressures, repeat the compression test.
(11) If the same cylinder or cylinders repeat an
abnormally low reading on the second compression
test, it could indicate the existence of a problem in
the cylinder in question.The recommended com-
pression pressures are to be used only as a
guide to diagnosing engine problems. An engine
should not be disassembled to determine the
cause of low compression unless some malfunc-
tion is present.
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE TEST
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing).
²Leaks between adjacent cylinders or into water
jacket.
²Any causes for combustion/compression pressure
loss.
WARNING: DO NOT REMOVE THE PRESSURE CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the pressure cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn the engine
OFF.
Clean spark plug recesses with compressed air.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
RSENGINE 3.3/3.8L9-83
ENGINE 3.3/3.8L (Continued)
ProCarManuals.com
(17) Remove battery shield.
(18) Remove charge air cooler outlet hose.
(19) Remove charge air cooler inlet hose (Fig. 6).
(20) Disconnect upper radiator hose at engine (Fig.
7).
(21) Disconnect lower radiator hose at engine (Fig.
7).
(22) Disconnet brake booster vacuum supply hose.
(23) Disconnect heater core return hose at engine.
(24) Disconnect egr solenoid vacuum line at brake
booster check valve.
(25) Disconnect fuel injector, cam sensor, boost
pressure/intake air temp sensor, fuel rail high pres-
sure, and egr solenoid connectors (Fig. 8).
(26) Disconnect generator electrical connectors.
(27) Disconnect coolant temp sensor and glow plug
electrical connectors.
(28) Disconnect injection pump and A/C compres-
sor electrical connectors.
(29) Disconnect starter electrical connectors.
(30) Disconnect ground wires at engine block.
(31) Raise vehicle on hoist.
(32) Disconnect oil temp sensor, oil pressure sen-
sor, engine speed sensor, and vehicle speed sensor
electrical connector (Fig. 9).(33) Remove front wheels.
(34) Remove the suspension cradle assembly (Refer
to 13 - FRAME & BUMPERS/FRAME/ENGINE
CRADLE CROSSMEMBER - REMOVAL).
(35) Remove both axle shaft assemblies (Refer to 3
- DIFFERENTIAL & DRIVELINE/HALF SHAFT -
REMOVAL).
(36) Disconnect the clutch slave cylinder quick dis-
connect line (RHD only)(Refer to 6 - CLUTCH/SLAVE
CYLINDER - REMOVAL).
(37) Disconnect reverse lamp connector.
(38) Disconnect shifter cables at the tranmission
(Refer to 21 - TRANSMISSION/TRANSAXLE/MAN-
UAL/GEAR SHIFT CABLE - REMOVAL).
(39) Disconnect exhaust pipe from the turbo-
charger downpipe and reposition to right side of vehi-
cle.
(40) Disconnect cabin heater coolant line (Refer to
24 - HEATING & AIR CONDITIONING/CABIN
HEATER/HEATER UNIT - REMOVAL).
(41) Remove front engine mount bracket retaining
bolts from lower radiator support
(42) Lower vehicle. Evacuate the A/C system
(Refer to 24 - HEATING & AIR CONDITIONING/
Fig. 6 CHARGE AIR COOLER HOSES
1 - COOLING MODULE
2 - BYPASS HOSE
3 - UPPER RADIATOR HOSE
4 - CHARGE AIR COOLER OULET HOSE
5 - CHARGE AIR COOLER INLET HOSE
6 - LOWER RADIATOR HOSE
7 - CHARGE AIR COOLER
Fig. 7 UPPER AND LOWER RADIATOR HOSES
1 - COOLANT BYPASS HOSE
2 - RADIATOR ASSEMBLY
3 - UPPER RADIATOR HOSE
4 - COOLING FAN
5 - LOWER RADIATOR HOSE
6 - CHARGE AIR COOLER
7 - RADIATOR BRACKET
RGENGINE9a-5
ENGINE 2.5L TURBO DIESEL (Continued)
ProCarManuals.com
INSTALLATION
INSTALLATION - 2.5L TURBO DIESEL ENGINE
(1) Reassembly engine and transmission assembly
and install on engine cradle.
(2) Position engine and cradle assembly under
vehicle.
(3) Slowly lower the vehicle down over the engine
and cradle assembly.
(4) Install right engine mount bolts. Torque to
54N´m (40 ft. lbs.)
(5) Install left engine mount through bolt. Torque
to 75N´m (55 ft. lbs.)
(6) Raise vehicle and engine from engine cradle.
(7) Attach front engine mount bracket to lower
radiator support. Torque to 54N´m (40 ft. lbs.)
(8) Connect cabin heater coolant hose.
(9) Connect exhaust pipe to the turbocharger
downpipe flange. Torque to 28 N´m (250 in. lbs.)
(10) Connect reverse lamp electrical connector at
transmission.
(11) Connect both shifter cables (Refer to 21 -
TRANSMISSION/TRANSAXLE/MANUAL/GEAR
SHIFT CABLE - INSTALLATION).
(12) Connect the clutch slave cylinder quick dis-
connect connector (RHD only)(Refer to 6 - CLUTCH/
SLAVE CYLINDER - INSTALLATION).
(13) Install engine harness into bracket on trans-
mission.
(14) Lower vehicle.
(15) Connect fuel supply and return lines.
(16) Connect A/C lines to A/C compressor. Torque
to 23N´m (17 ft. lbs.)
(17) Route engine wiring harnes to proper location.
(18) Connect engine harness ground cables to
engine block
(19) Connect starter solenoid electrical connector
and battery feed wire to starter. Torque to 10N´m (90
in. lbs.)
(20) Connect A/C compressor, injection pump, glow
plugs, and coolant temperature sensor electrical con-
nectors.
(21) Connect generator electrical connector. Torque
to 9N´m (75 in. lbs.)
(22) Connect the fuel injector, fuel pressure sensor,
boost pressure/intake air temp sensor, cam sensor,
and egr solenoid electrical connectors (Fig. 8).
(23) Connect egr solenoid vacuum supply line to
brake boost vacuum supply line.(24) Connect brake booster vacuum supply line.
(25) Connect heater core return hose to coolant
pipe.
(26) Connect lower radiator hose to engine (Fig. 7).
(27) Install charger air cooler inlet hose (Fig. 6).
(28) Install charge air cooler outlet hose (Fig. 6).
(29) Connect upper radiator hose to engine (Fig.
7).
(30) Install battery shield.
(31) Install coolant reserve pressure container
(Refer to 7 - COOLING/ENGINE/COOLANT RECOV-
ERY PRESS CONTAINER - INSTALLATION).
(32) Install power steering reservoir and bracket
(Fig. 4).
(33) Raise vehicle
(34) Connect oil pressure sensor, oil temperature
sensor, engine speed sensor, and vehicle speed sensor
electrical connector (Fig. 9).
(35) Install suspension cradle in vehicle (Refer to
13 - FRAME & BUMPERS/FRAME/ENGINE CRA-
DLE CROSSMEMBER - INSTALLATION).
(36) Install both axle shaft assemblies (Refer to 3 -
DIFFERENTIAL & DRIVELINE/HALF SHAFT -
INSTALLATION).
(37) Connect the power steering supply, pressure,
and return lines to power steering pump (Fig. 4).
(38) Install the power steering line brackets on oil
pan (Fig. 4).
(39) Install lower splash shield and side panels.
(40) Install both front wheel and tire assemblies.
(41) Lower vehicle.
(42) Install air cleaner housing, MAF sensor, and
air intake tube assembly (Fig. 3).
(43) Refill transmission to proper level (Refer to 21
- TRANSMISSION/TRANSAXLE/MANUAL/FLUID -
STANDARD PROCEDURE).
(44) Refill engine coolant (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(45) Recharge A/C system (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/REFRIGER-
ANT - STANDARD PROCEDURE) .
(46) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION) (Fig. 2).
(47) Connect negative battery cable.
INSTALLATION - ENGINE COVER
(1) Install engine cover on engine.
(2) Install the engine cover mounting bolts (Fig.
10).
RGENGINE9a-7
ENGINE 2.5L TURBO DIESEL (Continued)
ProCarManuals.com
1 second. Therefore, battery voltage is not supplied to
the fuel pump, ignition coil, fuel injectors and heated
oxygen sensors.
ENGINE START-UP MODE
This is an OPEN LOOP mode. If the vehicle is in
park or neutral (automatic transaxles) or the clutch
pedal is depressed (manual transaxles) the ignition
switch energizes the starter relay. The following
actions occur when the starter motor is engaged.
²If the PCM receives the camshaft position sensor
and crankshaft position sensor signals, it energizes
the Auto Shutdown (ASD) relay and fuel pump relay.
If the PCM does not receive both signals within
approximately one second, it will not energize the
ASD relay and fuel pump relay. The ASD and fuel
pump relays supply battery voltage to the fuel pump,
fuel injectors, ignition coil, (EGR solenoid and PCV
heater if equipped) and heated oxygen sensors.
²The PCM energizes the injectors (on the 69É
degree falling edge) for a calculated pulse width until
it determines crankshaft position from the camshaft
position sensor and crankshaft position sensor sig-
nals. The PCM determines crankshaft position within
1 engine revolution.
²After determining crankshaft position, the PCM
begins energizing the injectors in sequence. It adjusts
injector pulse width and controls injector synchroni-
zation by turning the individual ground paths to the
injectors On and Off.
²When the engine idles within 64 RPM of its
target RPM, the PCM compares current MAP sensor
value with the atmospheric pressure value received
during the Ignition Switch On (zero RPM) mode.
Once the ASD and fuel pump relays have been
energized, the PCM determines injector pulse width
based on the following:
²MAP
²Engine RPM
²Battery voltage
²Engine coolant temperature
²Inlet/Intake air temperature (IAT)
²Throttle position
²The number of engine revolutions since cranking
was initiated
During Start-up the PCM maintains ignition tim-
ing at 9É BTDC.
ENGINE WARM-UP MODE
This is an OPEN LOOP mode. The following inputs
are received by the PCM:
²Manifold Absolute Pressure (MAP)
²Crankshaft position (engine speed)
²Engine coolant temperature
²Inlet/Intake air temperature (IAT)
²Camshaft position²Knock sensor
²Throttle position
²A/C switch
²Battery voltage
²Vehicle speed
²Speed control
²O2 sensors
The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.
The PCM adjusts ignition timing and engine idle
speed. Engine idle speed is adjusted through the idle
air control motor.
CRUISE OR IDLE MODE
When the engine is at operating temperature this
is a CLOSED LOOP mode. During cruising or idle
the following inputs are received by the PCM:
²Manifold absolute pressure
²Crankshaft position (engine speed)
²Inlet/Intake air temperature
²Engine coolant temperature
²Camshaft position
²Knock sensor
²Throttle position
²Exhaust gas oxygen content
²A/C control positions
²Battery voltage
²Vehicle speed
The PCM adjusts injector pulse width and controls
injector synchronization by turning the individual
ground paths to the injectors On and Off.
The PCM adjusts engine idle speed and ignition
timing. The PCM adjusts the air/fuel ratio according
to the oxygen content in the exhaust gas (measured
by the upstream and downstream heated oxygen sen-
sor).
The PCM monitors for engine misfire. During
active misfire and depending on the severity, the
PCM either continuously illuminates or flashes the
malfunction indicator lamp (Check Engine light on
instrument panel). Also, the PCM stores an engine
misfire DTC in memory, if 2nd trip with fault.
The PCM performs several diagnostic routines.
They include:
²Oxygen sensor monitor
²Downstream heated oxygen sensor diagnostics
during open loop operation (except for shorted)
²Fuel system monitor
²EGR monitor (if equipped)
²Purge system monitor
²Catalyst efficiency monitor
²All inputs monitored for proper voltage range,
rationality.
²All monitored components (refer to the Emission
section for On-Board Diagnostics).
14 - 18 FUEL INJECTIONRS
FUEL INJECTION (Continued)
ProCarManuals.com
The PCM compares the upstream and downstream
heated oxygen sensor inputs to measure catalytic con-
vertor efficiency. If the catalyst efficiency drops below
the minimum acceptable percentage, the PCM stores a
diagnostic trouble code in memory, after 2 trips.
During certain idle conditions, the PCM may enter
a variable idle speed strategy. During variable idle
speed strategy the PCM adjusts engine speed based
on the following inputs.
²A/C sense
²Battery voltage
²Battery temperature or Calculated Battery Tem-
perature
²Engine coolant temperature
²Engine run time
²Inlet/Intake air temperature
²Vehicle mileage
ACCELERATION MODE
This is a CLOSED LOOP mode. The PCM recog-
nizes an abrupt increase in Throttle Position sensor
output voltage or MAP sensor output voltage as a
demand for increased engine output and vehicle
acceleration. The PCM increases injector pulse width
in response to increased fuel demand.
²Wide Open Throttle-open loop
DECELERATION MODE
This is a CLOSED LOOP mode. During decelera-
tion the following inputs are received by the PCM:
²A/C sense
²Battery voltage
²Inlet/Intake air temperature
²Engine coolant temperature
²Crankshaft position (engine speed)
²Exhaust gas oxygen content (upstream heated
oxygen sensor)
²Knock sensor
²Manifold absolute pressure
²Throttle position sensor
²IAC motor (solenoid) control changes in response
to MAP sensor feedback
The PCM may receive a closed throttle input from
the Throttle Position Sensor (TPS) when it senses an
abrupt decrease in manifold pressure. This indicates a
hard deceleration (Open Loop). In response, the PCM
may momentarily turn off the injectors. This helps
improve fuel economy, emissions and engine braking.
WIDE-OPEN-THROTTLE MODE
This is an OPEN LOOP mode. During wide-open-
throttle operation, the following inputs are used by
the PCM:
²Inlet/Intake air temperature
²Engine coolant temperature
²Engine speed
²Knock sensor²Manifold absolute pressure
²Throttle position
When the PCM senses a wide-open-throttle condi-
tion through the Throttle Position Sensor (TPS) it de-
energizes the A/C compressor clutch relay. This
disables the air conditioning system and disables
EGR (if equipped).
The PCM adjusts injector pulse width to supply a
predetermined amount of additional fuel, based on
MAP and RPM.
IGNITION SWITCH OFF MODE
When the operator turns the ignition switch to the
OFF position, the following occurs:
²All outputs are turned off, unless 02 Heater
Monitor test is being run. Refer to the Emission sec-
tion for On-Board Diagnostics.
²No inputs are monitored except for the heated
oxygen sensors. The PCM monitors the heating ele-
ments in the oxygen sensors and then shuts down.
FUEL CORRECTION or ADAPTIVE MEMORIES
DESCRIPTION
In Open Loop, the PCM changes pulse width with-
out feedback from the O2 Sensors. Once the engine
warms up to approximately 30 to 35É F, the PCM
goes into closed loopShort Term Correctionand
utilizes feedback from the O2 Sensors. Closed loop
Long Term Adaptive Memoryis maintained above
170É to 190É F unless the PCM senses wide open
throttle. At that time the PCM returns to Open Loop
operation.
OPERATION
Short Term
The first fuel correction program that begins func-
tioning is the short term fuel correction. This system
corrects fuel delivery in direct proportion to the read-
ings from the Upstream O2 Sensor.
The PCM monitors the air/fuel ratio by using the
input voltage from the O2 Sensor. When the voltage
reaches its preset high or low limit, the PCM begins
to add or remove fuel until the sensor reaches its
switch point. The short term corrections then begin.
The PCM makes a series of quick changes in the
injector pulse-width until the O2 Sensor reaches its
opposite preset limit or switch point. The process
then repeats itself in the opposite direction.
Short term fuel correction will keep increasing or
decreasing injector pulse-width based upon the
upstream O2 Sensor input. The maximum range of
authority for short term memory is 25% (+/-) of base
pulse-width. Short term is violated and is lost when
ignition is turned OFF.
RSFUEL INJECTION14-19
FUEL INJECTION (Continued)
ProCarManuals.com
31TH AUTOMATIC TRANSAXLE
TABLE OF CONTENTS
page page
31TH AUTOMATIC TRANSAXLE
DESCRIPTION.........................22
OPERATION...........................24
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRELIMINARY
DIAGNOSIS..........................24
DIAGNOSIS AND TESTING - ROAD TEST . . . 31
DIAGNOSIS AND TESTING - HYDRAULIC
PRESSURE TESTS....................32
DIAGNOSIS AND TESTING - TORQUE
CONVERTER HOUSING FLUID LEAKAGE . . . 35
DIAGNOSIS AND TESTING - CLUTCH AND
SERVO AIR PRESSURE TESTS..........35
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR......................37
REMOVAL.............................37
DISASSEMBLY.........................40
ASSEMBLY............................51
INSTALLATION.........................61
SCHEMATICS AND DIAGRAMS
31TH TRANSAXLE HYDRAULIC
SCHEMATICS........................64
SPECIFICATIONS
31TH AUTOMATIC TRANSAXLE..........72
SPECIAL TOOLS
31TH AUTOMATIC TRANSAXLE..........75
ACCUMULATOR
DESCRIPTION.........................79
OPERATION...........................79
BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND.............80
OPERATION
LOW/REVERSE (REAR) BAND...........80
ADJUSTMENTS
ADJUSTMENT - FRONT BAND...........80
ADJUSTMENTS - REAR BAND...........80
CLUTCH - FRONT
DESCRIPTION.........................82
OPERATION...........................82
DISASSEMBLY.........................82
ASSEMBLY............................84
CLUTCH - REAR
DESCRIPTION.........................86
OPERATION...........................86
DISASSEMBLY.........................87
ASSEMBLY............................89
FINAL DRIVE
DISASSEMBLY.........................91
ASSEMBLY............................94ADJUSTMENTS
ADJUSTMENT - DIFFERENTIAL BEARING . . 97
FLUID
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
AND CONDITION CHECK...............99
STANDARD PROCEDURE - FLUID AND
FILTER CHANGE......................99
GEAR SHIFT CABLE
REMOVAL............................101
INSTALLATION........................102
ADJUSTMENTS
GEARSHIFT CABLE ADJUSTMENT.......104
GOVERNOR
DESCRIPTION........................104
OPERATION..........................104
CLEANING...........................104
INSPECTION.........................104
OIL PUMP
DESCRIPTION........................105
OPERATION..........................105
STANDARD PROCEDURE - OIL PUMP
VOLUME CHECK.....................105
DISASSEMBLY........................106
CLEANING...........................106
INSPECTION.........................106
ASSEMBLY...........................107
PARK/NEUTRAL POSITION SWITCH
DIAGNOSIS AND TESTING - PARK/NEUTRAL
POSITION SWITCH...................107
REMOVAL............................107
INSTALLATION........................107
PLANETARY GEARTRAIN
DISASSEMBLY........................108
ASSEMBLY...........................109
SEAL - OIL PUMP
REMOVAL............................110
INSTALLATION........................110
SERVO - KICKDOWN
DESCRIPTION........................111
OPERATION..........................111
DISASSEMBLY........................111
CLEANING...........................112
INSPECTION..........................113
ASSEMBLY...........................113
SERVO - LOW/REVERSE
DESCRIPTION........................113
OPERATION..........................113
DISASSEMBLY........................114
CLEANING...........................114
RS31TH AUTOMATIC TRANSAXLE21-21
ProCarManuals.com
ASSEMBLY...........................115
SHIFT INTERLOCK SOLENOID
DESCRIPTION........................115
OPERATION..........................115
DIAGNOSIS AND TESTING - BRAKE/
TRANSMISSION SHIFT INTERLOCK
SOLENOID..........................117
REMOVAL............................117
INSTALLATION........................118
SOLENOID - TCC
DESCRIPTION........................119
OPERATION..........................119
REMOVAL............................119
INSTALLATION........................120
THROTTLE VALVE CABLE
REMOVAL............................120
INSTALLATION........................121
ADJUSTMENTS
THROTTLE VALVE LINKAGE
ADJUSTMENT.......................122
TORQUE CONVERTER
DESCRIPTION........................122
OPERATION..........................126
REMOVAL............................127
INSTALLATION........................127
TRANSFER SYSTEM - OUTPUT SHAFT/GEAR/
BEARING
REMOVAL............................128INSTALLATION........................131
ADJUSTMENTS
ADJUSTMENT - OUTPUT SHAFT BEARING . 135
TRANSFER SYSTEM - TRANSFER SHAFT/
GEAR/BEARING
REMOVAL............................137
INSTALLATION........................141
ADJUSTMENTS
ADJUSTMENT - TRANSFER SHAFT
BEARING...........................145
VALVE BODY
REMOVAL............................146
DISASSEMBLY........................148
CLEANING...........................154
INSPECTION.........................155
ASSEMBLY...........................155
INSTALLATION........................158
ADJUSTMENTS
HYDRAULIC CONTROL PRESSURE
ADJUSTMENTS......................160
VEHICLE SPEED SENSOR/PINION GEAR
REMOVAL............................160
INSTALLATION........................160
31TH AUTOMATIC
TRANSAXLE
DESCRIPTION
This transaxle combines torque converter, three
speed transmission, final drive gearing, and differen-
tial into a front wheel drive system.
Within this transaxle, there are three primary
areas:
(1) Main center line plus valve body.
(2) Transfer shaft center line (includes governor
and parking sprag).
(3) Differential center line.
Center distances between the main rotating parts
in these three areas are held precise to maintain a
low noise level.
The torque converter, transaxle area, and differen-
tial are housed in an integral aluminum die casting.
The differential oil sump is common with the
transaxle sump. Separate filling of the differen-
tial is NOT necessary.
The torque converter is attached to the crankshaft
through a flexible driving plate. Cooling of the con-
verter is accomplished by circulating the transaxle
fluid through a remote cooler. There are two types of
coolers used. An oil-to-water type cooler located in
the radiator side tank and/or an oil-to-air heatexchanger. The torque converter assembly is a sealed
unit that cannot be disassembled.
The transaxle fluid is filtered by an internal filter
attached to the lower side of the valve body assembly.
Engine torque is transmitted to the torque con-
verter and then through the input shaft to multiple-
disc clutches in the transaxle. The power flow
depends on the application of the clutches and bands.
Refer to Elements in Use Chart in Diagnosis and
Tests section.
The transaxle consists of:
²Two multiple-disc clutches
²An overrunning clutch
²Two servos
²A hydraulic accumulator
²Two bands
²Two planetary gear sets
This provides three forward ratios and a reverse
ratio. The common sun gear of the planetary gear
sets is connected to the front clutch by a driving
shell. The driving shell is splined to the sun gear and
front clutch retainer. The hydraulic system consists
of an oil pump and a single valve body which con-
tains all of the valves except the governor valves.
The transaxle sump and differential sump are both
vented through the dipstick. Output torque from the
main center line is delivered through helical gears to
the transfer shaft. This gear set is a factor in the
transaxle final drive (axle) ratio. The shaft also car-
21 - 22 31TH AUTOMATIC TRANSAXLERS
ProCarManuals.com
31TH Automatic Transaxle
1 - TORQUE CONVERTER CLUTCH
2 - TORQUE CONVERTER
3 - OIL PUMP
4 - FRONT CLUTCH
5 - REAR CLUTCH
6 - OVER-RUNNING CLUTCH7 - PLANETARY GEARS
8 - TRANSFER GEARS
9 - SHAFT
10 - GOVERNOR
11 - DIFFERENTIAL
RS31TH AUTOMATIC TRANSAXLE21-23
31TH AUTOMATIC TRANSAXLE (Continued)
ProCarManuals.com