DODGE NEON 1999 Service Repair Manual

Slide Hammer C-3752
Universal Handle C-4171
Bearing Installer C-4628
Seal Remover C-4680
Seal Installer C-4992
Torque Tool C-4995
Adapter C-4996
Installer L-4410
21 - 38 TRANSAXLEPL
SPECIAL TOOLS (Continued)

Special Jaw Set L-4518
Bearing Splitter 1130
Driver 6342
Seal Installer 6709
Bearing Remover 6768
Bench Fixture 6785
Remover 6786
Remover 6787
PLTRANSAXLE 21 - 39
SPECIAL TOOLS (Continued)

31TH AUTOMATIC TRANSAXLE
INDEX
page page
GENERAL INFORMATION
FLUID LEVEL AND CONDITION............. 41
GENERAL INFORMATION................. 40
SELECTION OF LUBRICANT............... 41
SPECIAL ADDITIVES..................... 41
DESCRIPTION AND OPERATION
AUTOMATIC TRANSMISSION SHIFTER/
IGNITION INTERLOCK.................. 42
CLUTCHES, BAND SERVOS, AND
ACCUMULATOR....................... 42
FLOW CONTROL VALVES................. 42
GEARSHIFT AND PARKING LOCK CONTROLS . 42
GOVERNOR............................ 43
HYDRAULIC CONTROL SYSTEM............ 42
PRESSURE REGULATING VALVES.......... 42
PRESSURE SUPPLY SYSTEM.............. 42
TORQUE CONVERTER CLUTCH SOLENOID
WIRING CONNECTOR.................. 43
TORQUE CONVERTER CLUTCH............ 42
DIAGNOSIS AND TESTING
CLUTCH AND SERVO AIR PRESSURE TESTS . 54
FLUID LEAKAGE-TRANSAXLE TORQUE
CONVERTER HOUSING AREA............ 55
HYDRAULIC PRESSURE TESTS............ 52
INTERLOCK SYSTEM OPERATION CHECK.... 55
ROAD TEST............................ 52
THREE SPEED TRANSAXLE DIAGNOSIS AND
TESTS.............................. 43
SERVICE PROCEDURES
ALUMINUM THREAD REPAIR.............. 58
FLUID AND FILTER CHANGE............... 56
FLUID DRAIN AND REFILL................. 57
FLUSHING COOLERS AND TUBES.......... 58
OIL PUMP VOLUME CHECK............... 58
REMOVAL AND INSTALLATION
GEARSHIFT CABLE...................... 59
GEARSHIFT MECHANISM................. 60
INTERLOCK MECHANISM................. 63
PARK/NEUTRAL STARTING AND BACK-UP
LAMP SWITCH........................ 64
PUMP OIL SEAL......................... 67
SHIFTER IGNITION INTERLOCK CABLE...... 61THROTTLE PRESSURE CABLE............. 60
TRANSAXLE........................... 64
VEHICLE SPEED SENSOR PINION GEAR..... 64
DISASSEMBLY AND ASSEMBLY
ACCUMULATOR-RECONDITION............ 83
DIFFERENTIAL REPAIR................... 95
FRONT CLUTCH-RECONDITION............ 78
FRONT PLANETARY AND ANNULUS GEAR-
RECONDITION........................ 81
KICKDOWN SERVO (CONTROLLED LOAD)-
RECONDITION........................ 83
LOW/REVERSE (REAR)
SERVO-RECONDITION.................. 82
OIL PUMP-RECONDITION................. 78
OUTPUT SHAFT REPAIR.................. 89
PARKING PAWL......................... 89
REAR CLUTCH-RECONDITION............. 79
TRANSAXLE........................... 67
TRANSFER SHAFT REPAIR................ 83
VALVE BODY RECONDITION............... 74
CLEANING AND INSPECTION
VALVE BODY........................... 99
ADJUSTMENTS
BAND ADJUSTMENT.................... 101
BEARING ADJUSTMENT PROCEDURES..... 101
DIFFERENTIAL BEARING................. 102
GEARSHIFT CABLE...................... 99
HYDRAULIC CONTROL PRESSURE
ADJUSTMENTS....................... 101
OUTPUT SHAFT BEARING................ 102
SHIFTER/IGNITION INTERLOCK SYSTEM.... 100
THROTTLE PRESSURE CABLE ADJUSTMENT
PROCEDURE........................ 100
TRANSFER SHAFT BEARING............. 103
SCHEMATICS AND DIAGRAMS
31TH TRANSAXLE HYDRAULIC SCHEMATIC . 105
SPECIFICATIONS
31TH AUTOMATIC TRANSAXLE............ 113
31TH TRANSAXLE TORQUE
SPECIFICATIONS..................... 113
SPECIAL TOOLS
31TH AUTOMATIC TRANSAXLE............ 114
GENERAL INFORMATION
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. The identifica-
tion markings and usage of the transaxle are charted
in Diagnosis and Tests.
21 - 40 TRANSAXLEPL

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. The final drive gearing is completed with
one of two gear ratios; 2.98 or 3.19 depending on
model and application.
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.
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, drain out a
sample for a double check.
SELECTION OF LUBRICANT
It is important that the proper lubricant be used in
these transmissions. Mopar ATF PLUS 3 (Automatic
Transmission Fluid- type 7176) should be used to aid
in ensuring optimum transmission performance. It is
important that the transmission fluid be maintained
at the prescribed level using the recommended fluids.
SPECIAL ADDITIVES
Chrysler Corporation does not recommend the
addition of any fluids to the transmission, other than
that fluid listed above. An exception to this policy is
PLTRANSAXLE 21 - 41
GENERAL INFORMATION (Continued)

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.
DESCRIPTION AND OPERATION
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.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.
AUTOMATIC TRANSMISSION SHIFTER/IGNITION
INTERLOCK
The Shifter/Ignition Interlock, is a mechanical
cable operated system (Fig. 1). It interconnects the
automatic transmission floor±mounted shifter to the
steering column ignition switch. The interlock system
locks the floor±mounted shift lever into the PARK
position whenever the ignition switch is in the LOCK
or ACCESSORY position. When the key is in the
OFF or RUN position, the shifter is unlocked and
will move into any position. Also the interlock system
prevents the ignition switch from being turned to
LOCK or ACCESSORY position, unless shifter is in
the PARK position.
GEARSHIFT AND PARKING LOCK CONTROLS
The transaxle is controlled by alever typegear-
shift incorporated within the console. The control has
21 - 42 TRANSAXLEPL
GENERAL INFORMATION (Continued)

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.
TORQUE CONVERTER CLUTCH SOLENOID WIRING
CONNECTOR
If the solenoid wiring connector is unplugged, the
torque converter will not engage (Fig. 2).
GOVERNOR
The governor can be serviced by removing the
transaxle oil pan and valve body assembly. The gov-
ernor can be unbolted from the governor support and
removed from the transaxle for reconditioning or
replacement.
When cleaning or assembling the governor, be sure
the governor valves move freely in the bores of the
governor body.
DIAGNOSIS AND TESTING
THREE SPEED TRANSAXLE DIAGNOSIS AND
TESTS
Automatic transaxle malfunctions may be caused
by four general conditions:
(1) Poor engine performance
(2) Improper adjustments
(3) Hydraulic malfunctions
(4) Mechanical malfunctions
Diagnosis of these problems should always begin
by checking the easily accessible variables; fluid level
and condition, gearshift cable adjustment, and throt-
tle pressure cable adjustment. Then perform a road
test to determine if the problem has been corrected
or that more diagnosis is necessary. If the problem
exists after the preliminary tests and corrections are
completed, hydraulic pressure tests should be per-
formed
31TH HYDRAULIC TROUBLE CODE CHARTS
The following charts should be used to help diag-
nose hydraulic or mechanical faults in the transaxle.
Fig. 1 Shifter Ignition Interlock System Components
Fig. 2 Torque Converter Clutch Solenoid Wiring
Connector
PLTRANSAXLE 21 - 43
DESCRIPTION AND OPERATION (Continued)

Diagnosis Guide
21 - 44 TRANSAXLEPL
DIAGNOSIS AND TESTING (Continued)

Diagnosis Guide
PLTRANSAXLE 21 - 45
DIAGNOSIS AND TESTING (Continued)

Diagnosis Guide
21 - 46 TRANSAXLEPL
DIAGNOSIS AND TESTING (Continued)

Diagnosis Guide
PLTRANSAXLE 21 - 47
DIAGNOSIS AND TESTING (Continued)