transmission DODGE NEON 2000 Service Workshop Manual

NOTE: Before removing the front suspension
crossmember from the vehicle, the location of the
crossmember must be scribed on the body of the
vehicle (Fig. 9). Do this so that the crossmember
can be relocated upon reinstallation against the
body of vehicle in the same location as before
removal. If the front suspension crossmember is
not reinstalled in exactly the same location as
before removal, the preset front wheel alignment
settings (caster and camber) will be lost.
(6) Using an awl, scribe a line (Fig. 25) marking
the location of where the front suspension crossmem-
ber is mounted against the body of the vehicle.(7) Position a transmission jack under the center
of the front suspension crossmember and raise it to
support the bottom of the crossmember.
(8) Loosen and completely remove the two front
bolts (one right and one left) attaching the front sus-
pension crossmember to the frame rails of vehicle.
The right side bolt can be viewed in the mounting
bolt figure (Fig. 24). The left side bolt is located in
the same location on the other side of the vehicle.
(9) Loosen the two rear bolts (one right and one
left) attaching the front suspension crossmember and
lower control arms to the body of the vehicle until
they release from the threaded tapping plates in the
body of the vehicle. Do not completely remove the
rear bolts because they are designed to disengage
from the body threads yet stay within the lower con-
trol arm rear isolator bushing. This allows the lower
control arm to stay in place on the crossmember. The
right side bolt can be viewed in the mounting bolt
figure (Fig. 24). The left side bolt is located in the
same location on the other side of the vehicle.
CAUTION: Lower the steering gear slowly, paying
special attention to the power steering fluid hoses
coming down from the power steering pump. Do
not strain or over extend the hoses coming to the
gear. Damage to the hoses or connecting hardware
could occur.
(10) Lower the front suspension crossmember
using the transmission jack enough to allow suffi-
cient access to the steering column lower coupling
(Fig. 26). When lowering front suspension crossmem-
ber, do not let crossmember hang from lower control
arms or power steering hoses. The weight should be
supported by the transmission jack.
(11) Remove the roll pin securing the steering col-
umn lower coupling to the power steering gear pinion
shaft using a roll pin punch (Fig. 27). Push the steer-
ing column lower coupling up and off of the power
steering gear pinion shaft.
INSTALLATION
(1) Push the column end of the steering column
lower coupling partway up through its hole in the
dash panel, then match the flat on the inside of the
steering column lower coupling to the flat on the
power steering gear pinion shaft and slide the cou-
pling onto the top of the pinion shaft. Align the roll
pin hole in the coupling with the groove in the pinion
shaft and install the roll pin through the coupling
until it is centered (Fig. 27).
(2) Center the power steering gear rack in its
travel.
(3) Using the transmission jack, raise the front
suspension crossmember and power steering gear
until the crossmember contacts its mounting spot
Fig. 24 Mounting Bolts
1 ± FRONT SUSPENSION CROSSMEMBER MOUNTING BOLTS
2 ± ENGINE TORQUE ISOLATOR STRUT MOUNTING BOLT
3 ± FRONT SUSPENSION CROSSMEMBER
Fig. 25 Marking Crossmember Location
1 ± SCRIBED LINE
2 ± FRONT SUSPENSION CROSSMEMBER
3±AWL
4 ± BODY
PLSTEERING 19 - 39
REMOVAL AND INSTALLATION (Continued)

against the body and frame rails of the vehicle. As
the crossmember is raised, carefully guide the steer-
ing column lower coupling up through its hole in the
dash panel.
(4) Start the two rear crossmember mounting bolts
into the tapping plates mounted in the body. The
right side bolt can be viewed in the mounting bolt
figure (Fig. 24). The left side bolt is located in the
same location on the other side of the vehicle. Next,
install the two front mounting bolts attaching front
suspension crossmember to frame rails of vehicle.
Lightly tighten all four mounting bolts to a approxi-mately 2 N´m (20 in. lbs.) to hold the front suspen-
sion crossmember in position.
NOTE: When reinstalling the front suspension
crossmember back in the vehicle, it is very impor-
tant that the crossmember be attached to the body
in exactly the same spot as when it was removed.
Otherwise, the vehicle's wheel alignment settings
(caster and camber) will be lost.
(5) Using a soft face hammer, tap the front suspen-
sion crossmember back-and-forth or side-to-side until
it is aligned with the previously scribed positioning
marks on the body of the vehicle (Fig. 25). Once the
front suspension crossmember is correctly positioned,
tighten the rear two crossmember mounting bolts to
a torque of 203 N´m (150 ft. lbs.), then tighten the
front two crossmember mounting bolts to a torque of
142 N´m (105 ft. lbs.).
(6) Fasten the engine torque strut to the right for-
ward corner of the front suspension crossmember
using its mounting bolt (Fig. 24). Follow the proce-
dure described in the ENGINE service manual group
to properly align and tighten the torque strut mount-
ing bolts.
(7) Reconnect the wiring harness connector to the
power steering fluid pressure switch (Fig. 23). Be
sure the locking tab on the wiring harness connector
is securely latched.
(8) Lower the vehicle to ground level.
(9) Install the dash-to-lower coupling seal in place
over the lower coupling's plastic collar.
NOTE: Verify that grease is present on the lip of
the dash-to-coupling seal where it contacts the cou-
pling's plastic collar.
(10) Inside the passenger compartment, reconnect
the steering column lower coupling to the steering
column upper coupling (Fig. 22). Install the coupling
pinch bolt an tighten the pinch bolt nut to a torque of
28 N´m (250 in. lbs.). Install the pinch bolt retainer
pin.
(11) Remove the steering wheel holder.
(12) While looking under the instrument panel at
the lower coupling, rotate the steering wheel back-
and-forth to verify that the lower coupling does not
squeak against the dash-to-coupling seal.
Fig. 26 Crossmember Lowered
1 ± STEERING COLUMN LOWER COUPLING
2 ± POWER STEERING GEAR
3 ± FRONT SUSPENSION CROSSMEMBER
4 ± TRANSMISSION JACK
Fig. 27 Coupling Roll Pin
1 ± STEERING COLUMN LOWER COUPLING
2 ± POWER STEERING GEAR PINION SHAFT
3 ± ROLL PIN
4 ± ROLL PIN PUNCH
19 - 40 STEERINGPL
REMOVAL AND INSTALLATION (Continued)

ferential case transfers torque from the ring gear to the
drive axles by means of differential side gears.
The NV T350 (A-578) transaxle internal components
can only be serviced by separating the case halves.
CAUTION: The transaxle output shaft is serviced as
a unit. No disassembly and reassembly is possible.
Damage to the transaxle may result.
TRANSAXLE IDENTIFICATION
The transaxle model, part number, build sequence
and date are shown on a bar code label that is
attached to the front of the transaxle. This informa-
tion is also shown on a metal I.D. tag that is
attached to the end cover of the transaxle (Fig. 1).
NOTE: Transaxles use various final drive gear
ratios in different vehicle applications. Therefore, it
is necessary that the correct transaxle assembly
number is used when ordering service parts.
NOTE: There are three different versions of this
transaxle. There are no external differences
between the models. Refer to the identification tag
on the transaxle to determine which transaxle the
vehicle is equipped with.
FLUID REQUIREMENTS
NV T350 (A-578) transaxles use MopartManual
Transaxle Lubricant (MS-9417).Hypoid gear lube,
engine oil, and/or automatic transmission fluid
should not be used in this transaxle.Hard shift-
ing effort, bearing, gear, and/or synchronizer failure
may occur if incorrect fluid is used.
SPECIAL ADDITIVES
The addition of any fluids to the transaxle, other
than the fluid listed above, is not recommended. An
exception to this policy is the use of special dyes to
aid in detecting fluid leaks. The use of transmission
sealers should be avoided, since they may adversely
affect seals.
SEALANTS
The sealant used to seal the transaxle case halves
and input bearing is MopartGasket Maker, Loctitet
518, or equivalent. The sealant used for the bearing
end plate cover is MopartRTV.
GEAR RATIOS
CAUTION: All gears and shafts must not be inter-
changed with other transaxles; they will not func-
tion correctly.The differential is a conventional arrangement of
gears that is supported by tapered roller bearings.
The final output gear turns the ring gear and differ-
ential assembly, thereby turning the drive axle
shafts.
All transaxles have a torque capacity of 136 lb. ft.
The gear ratios of each transaxle are shown in the
following chart. The chart also shows which transax-
les are available with the reverse±input shaft brake.
This brake allows easier shifting into reverse and
helps eliminate reverse gear clash.
Fig. 1 NV T350 (A-578) Transaxle Identification
1 ± LAST 3 DIGITS OF PART #
2 ± DATE CODE
3 ± PRODUCTION LINE SEQUENCE CODE
4 ± FULL PART #
5 ± END COVER
6 ± METAL TAG
7 ± NVG MODEL #
8 ± LABEL
21 - 2 TRANSAXLEPL
GENERAL INFORMATION (Continued)

ENGINE 2.0 SOHC EUROPE AND
U. S.1.8 BUX or 2.0L SALES
CODE ACR1.8 RIGHT HAND DRIVE
ONLY
GEAR
1st 3.54 3.54 3.54
2nd 2.13 2.13 2.13
3rd 1.36 1.36 1.36
4th 1.03 1.03 1.03
5th 0.72 0.81 0.81
FINAL DRIVE 3.55 3.94 3.94
REVERSE BRAKE NO YES YES
CLUTCH RELEASE
SYSTEMCABLE CABLE HYDRAULIC
GEARSHIFT PATTERN
The NV T350 (A-578) transaxle shift pattern is a
modified H±pattern (Fig. 2). Overdrive fifth and
reverse gears are in±line and outboard of the first
through fourth gear positions.
DIAGNOSIS AND TESTING
COMMON PROBLEM CAUSES
The majority of transaxle malfunctions are a result
of:
²Insufficient lubrication
²Incorrect lubricant
²Misassembled or damaged internal components
²Improper operation
HARD SHIFTING
Hard shifting may be caused by a misadjusted
crossover cable. If hard shifting is accompanied by
gear clash, synchronizer clutch and stop rings, or
gear teeth may be worn or damaged.Misassembled synchronizer components also cause
shifting problems. Incorrectly installed synchronizer
sleeves, struts, or springs can cause shift problems.
NOISY OPERATION
Before removing a transaxle to diagnose and repair
a noisy condition, verify the correct level and type of
fluid is installed in the transaxle. Abnormal wear
and damage to the internal components is frequently
the end result of insufficient/improper lubricant.
Refer to Fluid Requirements in this group.
Transaxle noise is most often a result of worn or
damaged components. Chipped, pitted, spalled and
broken gears or synchronizer teeth can cause noise.
Brinnelled or spalled bearings will generate noise.
Improperly assembled (missing, loose, or improp-
erly installed parts, etc) transaxles are likely to gen-
erate abnormal noise.
Squealing noises are commonly caused by defective
clutch release bearings and the reverse brake (if
equipped). Inspect the bearing cage and reverse cone
for signs of heat damage.
Gear rattle, gear clash, hard shifts, and premature
clutch disc wear can result from misalignment of the
transmission to the engine. Inspect for excessive
clutch dust in the clutch housing and oblonged
(mushroomed) dowel holes.
SLIPS OUT OF GEAR
Transaxle disengagement may be caused by mis-
aligned or damaged shift components, manufacturing
burrs on the gear teeth, or worn teeth on the drive
gears or synchronizer components. Incorrect assem-
bly, such as missing snap rings, also causes gear dis-
engagement.
Fig. 2 NV T350 (A-578) Shift Pattern
PLTRANSAXLE 21 - 3
GENERAL INFORMATION (Continued)

31TH AUTOMATIC TRANSAXLE
TABLE OF CONTENTS
page page
GENERAL INFORMATION
IN VEHICLE SERVICE.....................55
FLUID REQUIREMENTS...................55
DESCRIPTION AND OPERATION
31TH GENERAL INFORMATION..............55
FLUID LEVEL AND CONDITION..............56
TORQUE CONVERTER CLUTCH.............56
HYDRAULIC CONTROL SYSTEM.............56
PRESSURE SUPPLY SYSTEM...............56
PRESSURE REGULATING VALVES...........56
FLOW CONTROL VALVES..................56
CLUTCHES, BAND SERVOS, AND
ACCUMULATOR........................57
BRAKE TRANSMISSION SHIFT INTERLOCK
SYSTEM..............................57
GEARSHIFT AND PARKING LOCK CONTROLS . . 57
COOLER BYPASS VALVE..................57
TORQUE CONVERTER CLUTCH SOLENOID
WIRING CONNECTOR...................58
GOVERNOR.............................58
DIAGNOSIS AND TESTING
TRANSAXLE PRELIMINARY DIAGNOSIS.......58
ROAD TEST.............................65
HYDRAULIC PRESSURE TESTS.............66
CLUTCH AND SERVO AIR PRESSURE TESTS . . 68
FLUID LEAKAGE-TRANSAXLE TORQUE
CONVERTER HOUSING AREA.............70
BRAKE TRANSMISSION SHIFT INTERLOCK....70
SERVICE PROCEDURES
TRANSAXLE FLUID AND FILTER SERVICE.....70
ALUMINUM THREAD REPAIR...............71
FLUSHING COOLERS AND TUBES...........72
OIL PUMP VOLUME CHECK................72
REMOVAL AND INSTALLATION
GEARSHIFT CABLE.......................73
GEARSHIFT MECHANISM..................76
THROTTLE VALVE (KICKDOWN) CABLE.......77
BRAKE TRANSMISSION SHIFT INTERLOCK
CABLE...............................79
INTERLOCK MECHANISM..................82
VEHICLE SPEED SENSOR PINION GEAR......83
PARK/NEUTRAL STARTING AND BACK-UP
LAMP SWITCH.........................84TRANSAXLE AND TORQUE CONVERTER......84
PUMP OIL SEAL.........................88
DISASSEMBLY AND ASSEMBLY
TRANSAXLE............................89
VALVE BODY............................91
OIL PUMP.............................104
FRONT CLUTCH........................105
REAR CLUTCH ASSEMBLY................108
FRONT PLANETARY AND ANNULUS
GEAR-RECONDITION...................110
LOW/REVERSE (REAR) SERVO-
RECONDITION........................112
ACCUMULATOR-RECONDITION............113
KICKDOWN SERVO (CONTROLLED LOAD)-
RECONDITION........................113
TRANSFER SHAFT REPAIR................114
PARKING PAWL.........................121
OUTPUT SHAFT REPAIR..................121
DIFFERENTIAL REPAIR...................129
CLEANING AND INSPECTION
VALVE BODY...........................135
ADJUSTMENTS
GEARSHIFT CABLE......................135
THROTTLE VALVE CABLE ADJUSTMENT
PROCEDURE.........................136
BRAKE TRANSMISSION SHIFT INTERLOCK
SYSTEM.............................137
BAND ADJUSTMENT.....................138
HYDRAULIC CONTROL PRESSURE
ADJUSTMENTS.......................138
BEARING ADJUSTMENT PROCEDURES......138
OUTPUT SHAFT BEARING................139
DIFFERENTIAL BEARING.................139
TRANSFER SHAFT BEARING..............140
SCHEMATICS AND DIAGRAMS
31TH TRANSAXLE HYDRAULIC SCHEMATIC . . 142
SPECIFICATIONS
31TH AUTOMATIC TRANSAXLE.............150
31TH TRANSAXLE TORQUE SPECIFICATIONS . 150
SPECIAL TOOLS
31TH AUTOMATIC TRANSAXLE.............151
21 - 54 TRANSAXLEPL

GENERAL INFORMATION
IN VEHICLE SERVICE
The following components are serviceable in the
vehicle without transaxle removal:
²Valve Body Assembly
²Converter Clutch Solenoid
²Governor
²Vehicle Speed Sensor & Pinion
²Park/Neutral & Back-up Lamp Switch
²Transfer Gears and Transfer Shaft
²Low/Reverse Servo
²Kickdown Servo
²Accumulator
FLUID REQUIREMENTS
NOTE: The transmission and differential have a
common oil sump with an opening between the
two.
TRANSMISSION/DIFFERENTIAL
MopartATF+4 (Automatic Transmission Fluid
Type 9602) is required in this transaxle. Substitute
fluids must meet fluid specification MS-9602.
FLUID ADDITIVES
Chrysler Corporation strongly recommends against
the addition of any fluids to the transmission, other
than those automatic transmission fluids listed
above. Exceptions to this policy are the use of special
dyes to aid in detecting fluid leaks.
Various ªspecialº additives and supplements exist
that claim to improve shift feel/quality and converter
clutch operation, inhibit overheating, oxidation, var-
nish and sludge. These claims have not been sup-
ported to Chrysler's satisfaction and these additives
must not be used. The use of transmission ªsealersº
should also be avoided, since they may adversely
affect the integrity of tranmission seals.
DESCRIPTION AND OPERATION
31TH GENERAL INFORMATION
NOTE: Safety goggles should be worn at all times
when working on these transaxles.
This transaxle combines torque converter, three
speed transmission, final drive gearing, and differen-
tial into a front wheel drive system.
NOTE: Transaxle operation requirements are differ-
ent for each vehicle and engine combination. Some
internal parts will be different to provide for this.Therefore, when replacing parts, refer to the seven
digit part number stamped on rear of the transaxle
oil pan flange.
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 heat
exchanger. 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-
ries the governor and parking sprag. An integral heli-
cal gear on the transfer shaft drives the differential
ring gear.
PLTRANSAXLE 21 - 55

FLUID LEVEL AND CONDITION
NOTE: The transmission and differential sump have
a common oil sump with a communicating opening
between the two.
The torque converter fills in both the P (Park) and
N (Neutral) positions. Place the selector lever in P
(Park) to be sure that the fluid level check is accu-
rate.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground. This will ensure complete oil
level stabilization between differential and
transmission.The fluid should be at normal operat-
ing temperature (approximately 82É C. or 180É F.).
The fluid level is correct if it is in the HOT region
(cross-hatched area) on the dipstick (Fig. 1).
Low fluid level can cause a variety of conditions,
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy therefore, pressures will be
low and will build up slowly.
Improper filling also can raise the fluid level too
high. When the transaxle has too much fluid, the
gears churn up foam and cause the same conditions
that occur with a low fluid level.
In either case, the air bubbles can cause overheat-
ing, fluid oxidation, and varnishing. This can inter-
fere with normal valve, clutch, and servo operation.
Foaming also can result in fluid escaping from the
transaxle dipstick, where it may be mistaken for a
leak.
Along with fluid level, it is important to check the
condition of the fluid. When the fluid smells burned,
or is contaminated with metal or friction material
particles, a complete transaxle overhaul is needed.
Be sure to examine the fluid on the dipstick closely.
If there is any doubt about its condition, remove the
oil pan and inspect.
TORQUE CONVERTER CLUTCH
A torque converter clutch is standard on all vehi-
cles. The torque converter clutch is activated only in
direct drive and is controlled by the engine electron-
ics. A solenoid on the valve body, is powered by the
powertrain control module to activate the torque con-
verter clutch.
HYDRAULIC CONTROL SYSTEM
The hydraulic control system makes the transaxle
fully automatic, and has four important functions to
perform. The components of any automatic control
system may be grouped into the following basic
groups:
²Pressure supply system
²Pressure regulating valves
²Flow control valves
²Clutches
²Band servos
Taking each of these basic groups or systems in
turn, the control system may be described as follows:
PRESSURE SUPPLY SYSTEM
The pressure supply system consists of an oil pump
driven by the engine through the torque converter.
The single pump furnishes pressure for all hydraulic
and lubrication requirements.Oil pump housing
assemblies are available with preselected pump
gears.
PRESSURE REGULATING VALVES
The pressure regulating valve controls line pres-
sure dependent on throttle opening. The governor
valve transmits regulated pressure to the valve body
(in conjunction with vehicle speed) to control upshift
and downshift.
The throttle valve transmits regulated pressure to
the transaxle (dependent on throttle position) to con-
trol upshift and downshift.
FLOW CONTROL VALVES
The manual valve provides the different transaxle
drive ranges selected by the vehicle operator.
The 1-2 shift valve automatically shifts the tran-
saxle from first to second or from second to first,
depending on the vehicle operation.
The 2-3 shift valve automatically shifts the tran-
saxle from second to third or from third to second
depending on the vehicle operation.
Fig. 1 Transaxle Dipstick
1 ± TRANSAXLE DIPSTICK
21 - 56 TRANSAXLEPL
DESCRIPTION AND OPERATION (Continued)

The kickdown valve makes possible a forced down-
shift from third to second, second to first, or third to
first (depending on vehicle speed). This can be done
by depressing the accelerator pedal past the detent
feel near wide open throttle.
The shuttle valve has two separate functions and
performs each independently of the other. The first is
providing fast release of the kickdown band, and
smooth front clutch engagement when a lift-foot
upshift from second to third is made. The second
function is to regulate the application of the kick-
down servo and band when making third±to±second
kickdown.
The bypass valve provides for smooth application
of the kickdown band on 1-2 upshifts.
The torque converter clutch solenoid allows for the
electronic control of the torque converter clutch. It
also disengages the torque converter at closed throt-
tle. This is done during engine warm-up and part-
throttle acceleration.
The switch valve directs oil to apply the torque
converter clutch in one position. The switch valve
releases the torque converter clutch in the other posi-
tion.
CLUTCHES, BAND SERVOS, AND
ACCUMULATOR
The front and rear clutch pistons, and both servo
pistons, are moved hydraulically to engage the
clutches and apply the bands. The pistons are
released by spring tension when hydraulic pressure
is released. On the 2-3 upshift, the kickdown servo
piston is released by spring tension and hydraulic
pressure.
The accumulator controls the hydraulic pressure
on the apply±side of the kickdown servo during the
1-2 upshift; thereby cushioning the kickdown band
application at any throttle position.
BRAKE TRANSMISSION SHIFT INTERLOCK
SYSTEM
The Brake Transmission Shifter/Ignition Interlock
(BTSI) is a cable and solenoid operated system. It
interconnects the automatic transmission floor
mounted shifter to the steering column ignition
switch. The system locks the shifter into the PARK
position. The interlock system is engaged whenever
the ignition switch is in the LOCK or ACCESSORY
position. An additional electrically activated feature
will prevent shifting out of the PARK position unless
the brake pedal is depressed at least one-half inch. A
magnetic holding device integral to the interlock
cable is energized when the ignition is in the RUN
position. When the key is in the RUN position and
the brake pedal is depressed, the shifter is unlocked
and will move into any position. The interlock systemalso prevents the ignition switch from being turned
to the LOCK or ACCESSORY position, unless the
shifter is in the gated PARK position.
The following chart describes the normal operation
of the Brake Transmission Shift Interlock (BTSI) sys-
tem. If the ªexpected responseº differs from the vehi-
cle's response, then system repair and/or adjustment
is necessary.
GEARSHIFT AND PARKING LOCK CONTROLS
The transaxle is controlled by alever typegear-
shift incorporated within the console. The control has
six selector lever positions: P (Park), R (Reverse), N
(Neutral), and D (Drive), 2 (Second), and 1 (First).
The parking lock is applied by moving the selector
lever past a gate to the (P) position.Do not apply
the parking lock until the vehicle has stopped;
otherwise, a severe banging noise will occur.
COOLER BYPASS VALVE
Some 31TH transaxles are equipped with a cooler
bypass valve (Fig. 2). The valve is designed to bypass
the transaxle oil cooler circuit in cold weather condi-
tions, or when circuit restriction exceeds 25±30 p.s.i.
The valve consists of an integrated check ball and
spring, and a return tube to carry bypassed oil back
to the pump. The bypass valve is mounted to the
valve body transfer plate and is sealed with a rubber
o-ring seal (Fig. 3).
ACTION EXPECTED RESPONSE
1. Turn key to the ªOFFº
position.1. Shifter CAN be shifted
out of park.
2. Turn key to the
9ON/RUNº position.2. Shifter CANNOT be
shifted out of park.
3. Turn key to the
ªON/RUNº position and
depress the brake pedal.3. Shifter CAN be shifted
out of park.
4. Leave shifter in any
gear and try to return key
to the ªLOCKº or9ACCº
position.4. Key cannot be
returned to the ªLOCKº or
ªACCº position.
5. Return shifter to
ªPARKº and try to remove
the key.5. Key can be removed
(after returning to ªLOCKº
position).
6. With the key removed,
try to shift out of ªPARKº.6. Shifter cannot be
shifted out of ªPARKº.
NOTE: Any failure to meet these expected
responses requires system adjustment or repair.
PLTRANSAXLE 21 - 57
DESCRIPTION AND OPERATION (Continued)

Hydraulic pressure tests should be performed
when a transaxle internal failure is suspected. The
hydraulic flow charts, in the Schematics and Dia-
grams section of this group, outline fluid flow and
hydraulic circuitry. Circuit operation is provided for
all gear ranges. Normal working pressures are also
supplied for each of the gear ranges.
TRANSAXLE DIAGNOSIS CHARTS
CONDITION POSSIBLE CAUSES CORRECTION
HARSH ENGAGEMENT
(FROM NEUTRAL TO
DRIVE OR REVERSE)1. Fluid Level Low 1. Add Fluid
2. Throttle Linkage Misadjusted 2. Adjust linkage - setting may be too long.
3. Excessive Pinion Backlash 3. Check per Service Manual. Correct as
needed.
4. Hydraulic Pressure Incorrect 4. Check pressure. Remove, overhaul or
adjust valve body as needed.
5. Band Misadjusted. 5. Adjust rear band.
6. Valve Body Check Balls Missing. 6. Inspect valve body for proper check ball
installation.
7. Clutch, band or planetary
component Damaged.7. Remove, disassemble and repair
transmission as necessary.
8. Converter Clutch (if equipped)
Faulty.8. Replace converter and flush cooler and
line before installing new converter.
DELAYED ENGAGEMENT
(FROM NEUTRAL TO
DRIVE OR REVERSE)1. Fluid Level Low. 1. Correct level and check for leaks.
2. Filter Clogged. 2. Change filter.
3. Gearshift Linkage Misadjusted. 3. Adjust linkage and repair linkage if worn
or damaged.
4. Rear Band Misadjusted. 4. Adjust band.
5. Valve Body Filter Plugged. 5. Replace fluid and filter. If oil pan and old
fluid were full of clutch disc material and/or
metal particles, overhaul will be necessary.
6. Oil Pump Gears Worn/Damaged. 6. Remove transmission and replace oil
pump.
7. Hydraulic Pressure Incorrect. 7. Perform pressure test, remove
transmission and repair as needed.
8. Reaction Shaft Seal Rings
Worn/Broken.8. Remove transmission, remove oil pump
and replace seal rings.
9. Rear Clutch/Input Shaft, Rear
Clutch Seal Rings Damaged.9. Remove and disassemble transmission
and repair as necessary.
10. Governor Valve Stuck. 10. Remove and inspect governor
components. Replace worn or damaged
parts.
11. Regulator Valve Stuck. 11. Clean.
PLTRANSAXLE 21 - 59
DIAGNOSIS AND TESTING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NO DRIVE RANGE
(REVERSE OK)1. Fluid Level Low. 1. Add fluid and check for leaks if drive is
restored.
2. Gearshift Linkage/Cable
Loose/Misadjusted.2. Repair or replace linkage components.
3. Rear Clutch Burnt. 3. Remove and disassemble transmission
and rear clutch and seals. Repair/replace
worn or damaged parts as needed.
4. Valve Body Malfunction. 4. Remove and disassemble valve body.
Replace assembly if any valves or bores
are damaged.
5. Transmission Overrunning Clutch
Broken.5. Remove and disassemble transmission.
Replace overrunning clutch.
6. Input Shaft Seal Rings Worn/
Damaged.6. Remove and disassemble transmission.
Replace seal rings and any other worn or
damaged parts.
7. Front Planetary Failed Broken. 7. Remove and repair.
NO DRIVE OR REVERSE
(VEHICLE WILL NOT
MOVE)1. Fluid Level Low. 1. Add fluid and check for leaks if drive is
restored.
2. Gearshift Linkage/Cable
Loose/Misadjusted.2. Inspect, adjust and reassemble linkage
as needed. Replace worn/damaged parts.
3. Filter Plugged. 3. Remove and disassemble transmission.
Repair or replace failed components as
needed. Replace filter. If filter and fluid
contained clutch material or metal particles,
an overhaul may be necessary. Perform
lube flow test. Flush oil. Replace cooler as
necessary.
4. Oil Pump Damaged. 4. Perform pressure test to confirm low
pressure. Replace pump body assembly if
necessary.
5. Valve Body Malfunctioned. 5. Check press and inspect valve body.
Replace valve body (as assembly) if any
valve or bore is damaged. Clean and
reassemble correctly if all parts are in good
condition.
6. Transmission Internal Component
Damaged.6. Remove and disassemble transmission.
Repair or replace failed components as
needed. Remove and disassemble
transmission. Repair or replace failed
components as needed.
7. Park Sprag not Releasing - Check
Stall Speed, Worn/Damaged/Stuck.7. Remove, disassemble, repair.
8. Torque Converter Damage. 8. Inspect and replace as required.
21 - 60 TRANSAXLEPL
DIAGNOSIS AND TESTING (Continued)