1994 JEEP CHEROKEE brake fluid

PRESSURE TEST ANALYSIS
If pressures in D and Reverse are higher than
specified, check for the following:
²throttle cable loose, worn, binding or out of adjust-
ment
²throttle valve, downshift plug, throttle cam, or pri-
mary regulator valve are sticking, worn or damaged
If pressures in D and Reverse are lower than spec-
ified, check for following:
²throttle cable loose, worn, binding or out of adjust-
ment
²throttle valve, downshift plug, throttle cam stick-
ing, worn or damaged
²primary regulator valve sticking, worn, or dam-
aged
²oil pump gears or housing worn or damaged
²overdrive clutch worn or damaged
If pressures are low in D range only, check for fol-
lowing:
²forward clutch worn or damaged
²fluid leakage in D range circuit (component seal
and O-rings)
If pressures are low in Reverse only, check for fol-
lowing:
²shift cable and manual valve out of adjustment
²fluid leakage in reverse circuit (component seal
and O-rings)
²direct clutch worn or damaged
²first/reverse brake worn or damaged
TORQUE CONVERTER STALL TEST
Stall testing checks the holding ability of the trans-
mission clutches and brakes and of the torque con-
verter stator overrunning clutch.
(1) Be sure transmission fluid is at normal operat-
ing temperature.
(2) Connect tachometer to engine. Position tachom-
eter so it can be viewed from drivers seat.
(3) Apply parking brakes and block wheels.
(4) Apply and hold service brakes.
(5) Shift transfer case into 2H position. On models
with NP249 transfer case, leave transfer case in 4H
position.
(6) Start engine.
WARNING: DO NOT ALLOW ANYONE TO STAND AT
THE FRONT OR REAR OF THE VEHICLE DURING
THE TEST.
(7) Shift transmission into D range.
(8) Press accelerator pedal to wide open throttle
position and note maximum engine rpm. Stall speed
should be 2100 to 2400 rpm in D range.
CAUTION: Do not maintain wide open throttle for
more than 3-4 seconds at a time.(9) Release throttle and shift transmission into
Neutral. Allow transmission fluid to cool for 15-20
seconds.
(10) Shift transmission into Reverse.
(11) Press accelerator down to wide open throttle
position and note maximum engine rpm. Stall speed
should be 2100-to-2400 rpm in Reverse.
STALL SPEED TEST ANALYSIS
If engine rpm is lower than specified in D and Re-
verse, check for the following:
²engine output/performance insufficient
²stator overrunning clutch in torque converter not
holding if engine speed was 1500 rpm or less.
If stall speed in D range is higher than specified,
check for the following:
²line pressure low
²forward clutch slipping
²No. 2 one-way clutch not holding
²overdrive one-way clutch not holding
If stall speed in Reverse was higher than specified,
check for the following:
²line pressure low
²direct clutch slipping
²first/ reverse brake slipping
²overdrive one-way clutch not holding
If stall speeds were higher than specified in both D
and Reverse, check for the following:
²low fluid level
²line pressure low
²overdrive one-way clutch not holding
TIME LAG TEST
This test checks general condition of the overdrive
clutch, forward clutch, rear clutch and first/reverse
brake. Condition is indicated by the amount of time
required for clutch/brake engagement with the en-
gine at curb idle speed. Engagement time is mea-
sured for D and Reverse positions. A stop watch is
recommended for test accuracy.
TEST PROCEDURE
(1) Check and adjust transmission fluid level if
necessary.
(2) Bring transmission to normal operating tem-
perature.
(3) Apply parking brakes and turn off air condi-
tioning unit.
(4) Shift transfer case into 2H range. On models
with NP249 transfer case, leave transfer case in 4H
range.
(5) Start engine and check curb idle speed. Adjust
speed if necessary. Curb idle must be correct to en-
sure accurate test results.
(6) Shift transmission into Neutral and set stop
watch.
(7) During following test steps, start stop watch as
soon as shift lever reaches D and Reverse ranges.
JAW-4 TRANSMISSION DIAGNOSIS 21 - 169

AW-4 IN-VEHICLE SERVICE
INDEX
page page
Accumulator Pistons and Springs........... 179
Adapter Housing Seal Replacement.......... 182
Checking Fluid Level and Condition.......... 173
Manual Valve Shaft Seal Replacement....... 178
Park Interlock Cable Adjustment............ 186
Park Rod and Pawl Service................ 181
Park/Neutral Position Switch............... 173
Second Coast Brake Servo................ 181
Shift Cable Adjustment................... 186
Speed Sensor.......................... 182Speed Sensor RotorÐSpeedometer Drive Gear . 183
Throttle Position Sensor (TPS) Service....... 184
Transmission Control Module (TCM) Service . . . 173
Transmission Cooler Line Fittings........... 187
Transmission Cooler Service............... 187
Transmission Throttle Cable Adjustment....... 185
Transmission Throttle Cable Replacement..... 184
Transmission Valve Body Installation......... 177
Transmission Valve Body Removal.......... 176
Transmission Valve Body Solenoids.......... 175
CHECKING FLUID LEVEL AND CONDITION
Recommended fluid for AW-4 transmissions is Mo-
par Dexron IIE/Mercon. Mopar Dexron II may be
used if Mercon fluid is not readily available.
CHECKING FLUID LEVEL
(1) Be sure transmission fluid is at normal operat-
ing temperature. Normal operating temperature is
reached after approximately 15 miles (25 km) of op-
eration.
(2) Position vehicle on level surface. This is impor-
tant for an accurate fluid level check.
(3) Shift transmission through all gear ranges and
back to Park.
(4) Apply parking brakes.
(5) Verify that transmission is in Park.
(6) Wipe off dipstick handle to prevent dirt from
entering fill tube. Then remove dipstick and check
fluid level and condition.
(7) Correct fluid level isto FULL mark on dip-
stick when fluid is at normal operating temper-
ature(Fig. 1).
(8) If fluid level is low, top off level with Mopar
Dexron IIE/Mercon. Mopar Dexron II may also be
used if Mercon is not available.Do not overfill
transmission. Add only enough fluid to bring
level to Full mark.
CHECKING FLUID CONDITION
Inspect the appearance of the fluid during the fluid
level check. The fluid should be clear and free of for-eign material or particles. If the fluid is dark brown
or black in color and smells burnt, the fluid has been
overheated and should be replaced.
Transmission operation should also be checked if
the fluid is severely discolored and contains quanti-
ties of foreign material, metal particles, or clutch disc
friction material.
A small quantity of friction material or metal
particles in the oil pan is normal. The particles
are usually generated during the break-in pe-
riod and indicate normal seating of the various
transmission components.
TRANSMISSION CONTROL MODULE (TCM)
SERVICE
Use the DRB II scan tool to diagnose transmission
control module function whenever a fault is sus-
pected. Replace the module only when actually faulty.
TRANSMISSION CONTROL MODULE
REPLACEMENT
The transmission control module is mounted under
the instrument panel. On left hand drive models, it is
at the driver side of the lower finish panel (Fig. 2).
On right hand drive models, it is at the passenger
side of the lower finish panel (Fig. 3).
To remove the module, disconnect the wire harness,
remove the mounting screws and remove the module
from the finish panel. Tighten the module mounting
screws securely after installation. Also be sure the
wire harness is not twisted, kinked or touching any
body panels.
PARK/NEUTRAL POSITION SWITCH
SWITCH TESTING
Test switch continuity with an ohmmeter. Discon-
nect the switch and check continuity at the connector
terminal positions and in the gear ranges indicated
in Figure 3. Switch continuity should be as follows:Fig. 1 Transmission Fluid Level
JAW-4 IN-VEHICLE SERVICE 21 - 173

SECOND COAST BRAKE SERVO
SERVO OVERHAUL
(1) Remove valve body as outlined in this section.
(2) Remove servo piston cover snap ring with snap
ring pliers (Fig. 30).
(3) Remove servo piston and cover with com-
pressed air. Apply compressed air through oil hole in
servo boss to ease piston out of bore (Fig. 31).
(4) Remove and discard seal and O-rings from
cover and piston (Fig. 32). Inspect E-ring, piston,
spring and retainer, piston rod and piston spring. Re-
place worn or damaged parts.
(5) Install new seals on cover and piston.
(6) Lubricate servo components with transmission
fluid.
(7) Assemble and install servo components in case.
Be sure servo piston rod is properly engaged in the
second coast brake band.
(8) Compress cover and piston and install cover
snap ring.
(9) Install valve body, oil screen and oil pan. Use
Mopar or Loctite 599 on oil pan sealing surface.
PARK ROD AND PAWL SERVICE
(1) Remove valve body as outlined in this section.
(2) Remove bolts attaching park rod bracket to
case (Fig. 33).(3) Remove park rod from manual valve shaft sec-
tor (Fig. 34).
(4) Remove park rod.
(5) Remove park pawl, pin and spring (Fig. 35).
(6) Examine park rod, pawl, pin and spring. Re-
place any component that is worn or damaged.
(7) Install pawl in case. Insert pin and install
spring. Be sure spring is positioned as shown in Fig-
ure 35.
Fig. 29 Accumulator Pistons, Springs And Spacers
Fig. 30 Removing/Installing Servo Piston Cover
Snap Ring
Fig. 31 Removing Servo Cover And Piston
JAW-4 IN-VEHICLE SERVICE 21 - 181

(8) Install park rod and bracket (Fig. 33). Tighten
bracket bolts to 10 Nzm (7 ft. lbs.) torque.
(9) Install valve body, oil screen and oil pan as out-
lined in this section.
ADAPTER HOUSING SEAL REPLACEMENT
(1) Raise vehicle.
(2) Disconnect or remove components necessary to
gain access to seal (e.g. propeller shaft, crossmember,
shift linkage, transfer case, exhaust components,
hoses, wires).
(3) Remove dust shield and remove seal from
adapter housing (Fig. 36).
(4) Install new seal with appropriate size seal in-
staller and install dust shield.(5) Reinstall components removed to gain access to
seal.
(6) Top off transmission fluid if necessary.SPEED SENSOR
SPEED SENSOR TESTING
Test the speed sensor with an ohmmeter. Place the
ohmmeter leads on the terminals in the sensor con-
nector (Fig. 37).
Rotate the transmission output shaft and observe
the ohmmeter needle. The needle should deflect indi-
cating the switch is opening/closing as the rotor
Fig. 34 Removing/Installing Park Rod
Fig. 35 Removing/Installing Park Pawl, Pin And
Spring
Fig. 32 Second Coast Brake Servo Components
Fig. 33 Removing/Installing Park Rod Bracket
21 - 182 AW-4 IN-VEHICLE SERVICEJ

TRANSMISSION COOLER SERVICE
Main Cooler
The transmission main cooler is located in the ra-
diator. The main cooler can be flushed when neces-
sary, however, the cooler is not a repairable
component. If the cooler is damaged, plugged, or
leaking, the radiator will have to be replaced.
Auxiliary Cooler
The auxiliary cooler is mounted in front of the ra-
diator at the driver side of the vehicle (Fig. 48). The
cooler can be flushed when necessary, while mounted
in the vehicle. The cooler can also be removed for ac-
cess, repair, or replacement as needed.
The main and auxiliary coolers should both be
flushed whenever a transmission or converter clutch
malfunction generates sludge, debris, or particles of
clutch friction material.
Cooler Service
The main cooler (and radiator) and the auxiliary
cooler can be removed for service or access to other
components. Auxiliary cooler removal requires that
the front bumper and radiator support be removed
for access to the cooler lines and attaching bracket.
REVERSE FLUSHING MAIN AND AUXILIARY
COOLERS AND COOLER LINES
Reverse flushing the cooler and lines will prevent
sludge and particles from flowing back into the
transmission after repair. The flushing procedure ap-
plies to standard (in-radiator) coolers and auxiliary
coolers equally.
Pressure equipment is preferred for reverse flush-
ing. However, reverse flushing can be performed us-
ing hand operated equipment as described in the
following procedure.
(1) Disconnect cooler lines at transmission and at
auxiliary cooler (Figs. 48 and 49).
(2) Position drain pan under cooler line to catch
material flushed through coolers and lines.
(3) Reverse flush each cooler using hand operated
suction gun filled with mineral spirits. Insert gun
nozzle (or hose) into cooler inlet (return) line. Then
force mineral spirits through into line and through
cooler.(4) Continue reverse flushing until fluid exiting in-
let (pressure) line is clear and free of debris/residue.
(5) Replace radiator if fluid cannot be pumped
through main cooler. Replace auxiliary cooler if leaks
are evident, or if fluid cannot be pumped through it.
(6) Clear flushing materials from coolers and lines
with short pulses of compressed air. Insert air gun
nozzle into cooler inlet (return) line and continue
short pulses of air until all fluid is cleared from
cooler and lines.
(7) Pump one quart of fresh automatic transmis-
sion fluid through cooler and lines before reconnect-
ing cooler lines.
FLOW TESTING TRANSMISSION MAIN
COOLER
Cooler flow is checked by measuring the amount of
fluid flow through the cooler in a 20 second time pe-
riod. The test is performed with the engine running
and transmission in neutral. Fluid is then pumped
through the cooler by the transmission oil pump.
(1) Disconnect cooler inlet line at transmission fit-
ting.
(2) Securely attach hose to end of inlet line and po-
sition line in a one quart test container.
(3) Add extra quart of fluid to transmission.
(4) Use stopwatch to check flow test time.
(5) Shift transmission into neutral and set parking
brake.
(6) Start and run engine at curb idle speed and im-
mediately note cooler flow. Approximately one quart
of fluid should flow into test container in 20 second
period.
(7) If cooler flow is intermittent, flows less than
one quart in 20 seconds, or does not flow at all,
cooler is faulty and must be replaced.
TRANSMISSION COOLER LINE FITTINGS
Quick disconnect fittings are used at the transmis-
sion cooler line connections. The fitting seals and
guides are serviceable.
Replace the seals and guides whenever the fittings
exhibit leakage, or will not properly snap into place.
JAW-4 IN-VEHICLE SERVICE 21 - 187

During overhaul assembly operations, lubricate the
transmission components with Jeep or Mopar Mer-
conŸ automatic transmission fluid or petroleum jelly
as indicated. Petroleum jelly should be used to prelu-
bricate thrust bearings, washers and races. It can
also be used to hold parts in position during assem-
bly.
Soak replacement clutch and brake pack com-
ponents in transmission fluid for at least 30
minutes before installation.
MANUAL VALVE SHAFT OVERHAUL
(1) Cut shaft spacer sleeve in half with chisel and
remove it from lever and shaft (Fig. 2).
(2) Remove shift sector retaining pin with pin
punch (Fig. 3).
(3) Pull shaft out of case and remove manual lever.
(4) Carefully pry shaft seals from case.
(5) Lubricate new seals with petroleum jelly and
install them in case (Fig. 4).
(6) Install new spacer sleeve on shift sector (Fig.
5).
(7) Install sector and sleeve on shaft and install
shaft in case.
(8) Align sector and sleeve and install new retain-
ing pin.
(9) Align notch in sleeve with depression in sector
and stake sleeve in two places. Be sure lever and
shaft rotate smoothly.
Fig. 1 Manual Valve Shaft Components
Fig. 2 Cutting Shaft Spacer Sleeve
Fig. 3 Removing/Installing Sector Retaining Pin
JAW-4 TRANSMISSION OVERHAUL 21 - 205

UNDERBODY COMPONENTS
INDEX
page page
Catalytic Converter/Muffler/Tailpipe Support
Brackets............................. 85
Front Skid Plate......................... 84
Fuel and Brake Fluid Tube Retainer Clip....... 86
Fuel Filler Hose Splash ShieldÐXJ Vehicles.... 86
Fuel Filter Bracket........................ 86Fuel Tank Skid Plate...................... 84
Fuel Tank Support Strap................... 86
Rear Tow HookÐXJ Vehicles............... 87
Service Information....................... 84
Trailer Hitches........................... 88
Transfer Case Skid Plate.................. 84
SERVICE INFORMATION
In some cases, components in the following proce-
dures either support, or are concealed by other com-
ponents. When necessary, refer to component
removal procedure for service access.
FRONT SKID PLATE
REMOVAL
(1) Remove the screws that attach skid plate to
side sills (Fig. 1).
(2) Remove the nuts that attach the skid plate to
the crossmember (Fig. 1).
(3) Remove the skid plate from the vehicle (Fig. 1).
INSTALLATION
(1) Position the skid plate at front crossmember
and side sills (Fig. 1).
(2) Install the nuts to attach the skid plate to
crossmember.(3) Install the screws to attach skid plate to side
sills.
TRANSFER CASE SKID PLATE
REMOVAL
(1) Support the skid plate.
(2) Remove the bolts that attach the skid plate to
the transmission support crossmember and frame sill
(Fig. 2).
(3) Remove the support and skid plate from the ve-
hicle.
INSTALLATION
(1) Position and support the skid plate at the
frame sill and transmission support crossmember
(Fig. 2).
(2) Attach the skid plate to the frame sill and
crossmember with bolts. Tighten bolts to 22 Nzm (16
ft-lbs) torque.
FUEL TANK SKID PLATE
REMOVALÐXJ VEHICLES
(1) Position a support under skid plate.
(2) Remove the bolts that attach skid plate to un-
derbody side rails (Figs. 3 and 4).
Fig. 1 Front Skid Plate Removal/Installation
Fig. 2 Transfer Case Skid Plate
23 - 84 BODY COMPONENTSÐXJ VEHICLESJ

(3) Attach catalytic converter, muffler or tailpipe
insulator to support hanger to insulator.
FUEL AND BRAKE FLUID TUBE RETAINER CLIP
REMOVAL
(1) Remove the fuel/brake fluid tubes from clip
grooves.
(2) As applicable, pry serrated clip outward and re-
move it from frame rail hole, or remove stand-off
bracket screw.
INSTALLATION
(1) Position clip at the frame/panel hole.
(2) As applicable, force serrated clip inward and
seat it against the frame/panel, or install the stand-
off bracket screw.
(3) Insert fuel/brake fluid tubes in clip grooves and
press inward to seat them.
FUEL FILTER BRACKET
REMOVAL
(1) Remove screws that attach fuel filter bracket to
frame rail.
(2) Remove the screw from fuel filter bracket
clamp.
(3) Remove the clamp and fuel filter from bracket.
(4) Remove the bracket from filter.
INSTALLATION
(1) Position fuel filter bracket on filter.
(2) Position clamp on bracket and install screw.
Tighten screw to 8 Nzm (74 in-lbs) torque.(3) Position fuel filter bracket on frame rail.
(4) Install the screws that attach bracket to frame
rail. Tighten screws to 42 Nzm (31 ft-lbs) torque.
FUEL FILLER HOSE SPLASH SHIELDÐXJ
VEHICLES
REMOVAL
(1) Remove the screws that attach fuel filler hose
splash shield to wheelhouse panel and frame rail.
(2) Remove the hose splash shield from wheelhouse
panel and frame rail (Fig. 7).
INSTALLATION
(1) Position fuel filler hose splash shield at wheel-
house panel and frame rail.
(2) Install screws to attach splash shield to wheel-
house panel and frame rail.
FUEL TANK SUPPORT STRAP
SERVICE INFORMATION
XJ fuel tank support straps are attached to the un-
Fig. 4 Fuel and Brake Tube Serrated/Bracket-Type
Retainer ClipsÐXJ Vehicles
Fig. 5 Fuel Filter Bracket Removal/Installation
Fig. 6 Fuel Filter Bracket Clamp
Removal/Installation
23 - 86 BODY COMPONENTSÐXJ VEHICLESJ