2002 JEEP GRAND CHEROKEE Transmission

PROPELLER SHAFT - FRONT
REMOVAL
NOTE: Different length propeller shafts are used for
different drivetrain applications. Ensure that the
correct propeller shaft is used.
(1) Place vehicle on floor or drive-on hoist with full
weight of vehicle on suspension.
(2) Shift the transmission and transfer case, if nec-
essary, into the Neutral position.
(3) Measure the distance from the face of the C/V
joint cup to the end of the C/V joint boot (Fig. 8).
(4) The correct length is 142.7 mm (5.61 in.).
NOTE: If the measurement is not correct, the wrong
shaft may have been installed or a mating compo-
nent (front axle or transfer case) may be installed
incorrectly. Investigate and correct as necessary.
(5) Mark a line across the companion flange at the
transfer case and C/V joint at the rear of the front
propeller shaft for installation reference.
(6) Mark a line across the C/V joints and the pin-
ion companion flanges for installation reference.
(7) Remove bolts from the front C/V joint to the
pinion companion flange.
(8) Remove bolts from the rear C/V joint to the
transfer case companion flange.
(9) Push the propeller shaft forward to clear trans-
fer case companion flange and remove the shaft.
INSTALLATION
NOTE: Different length propeller shafts are used for
different drivetrain applications. Ensure that the
correct propeller shaft is used.
(1) Install the shaft between companion flanges.
(2) The shaft should rotate freely in the pinion
flange.
(3) Align marks on the companion flanges with the
marks on the C/V joints.
(4) Install bolts to the front C/V joint and tighten
bolts to 32 N´m (24 ft. lbs.).
(5) Install the bolts to the rear C/V joint and
tighten bolts to 32 N´m (24 ft. lbs.).
(6) Verify propeller shaft length.
(7) Lower vehicle.
PROPELLER SHAFT - FRONT
4.7L
REMOVAL
(1) Raise and support vehicle.
(2) Remove crossmember/skid plate as necessary to
gain access to the propeller shaft.
(3) Shift transmission and transfer case, if neces-
sary into Neutral.
(4) Mark a line across the yoke at the transfer
case, link yoke and propeller shaft yoke at the rear of
the front propeller shaft for installation reference
(Fig. 9).
(5) Mark a line across the propeller shaft yoke and
pinion shaft yoke for installation reference.
Fig. 8 MEASUREMENT
1 - C/V JOINT CUP
2 - C/V BOOT END
3 - MEASUREMENT
Fig. 9 REFERENCE MARKS ON YOKES
1 - REFERENCE MARKS
3 - 6 PROPELLER SHAFTWJ

(6) Remove the U-joint strap bolts at the pinion
shaft yoke (Fig. 10).
(7) Remove bolts holding rear universal joint to
the transfer case yoke.
(8) Separate the rear universal joint from the
transfer case yoke.
(9) Push rear of propeller shaft upward to clear
transfer case yoke.
(10) Separate front universal joint from front axle.
(11) Separate propeller shaft from vehicle.
INSTALLATION
(1) Position front propeller shaft under vehicle
with rear universal joint over the transfer case yoke.
(2) Place front universal joint into the axle pinion
yoke.
(3) Align mark on the rear link yoke and universal
joint to the mark on the transfer case yoke.
(4) Loosely install bolts to hold universal joint to
transfer case yoke.
(5) Align mark on front universal joint to the mark
on the axle pinion yoke.
(6) Tighten the U-joint strap/clamp bolts at the
axle yoke to 19 N´m (14 ft. lbs.).
(7) Tighten the universal joint to transfer case
bolts to 27 N´m (20 ft. lbs.).
(8) Lower the vehicle.
PROPELLER SHAFT - REAR
REMOVAL
(1) Raise and support vehicle on safety stands.
(2) Shift the transmission and transfer case if nec-
essary, to their neutral positions.
(3) Mark a line across the axle pinion yoke and the
propeller shaft yoke for installation reference.
(4) Remove the bolts holding the universal joint
clamps to the pinion yoke.
(5) Slide the slip yoke off of the transmission, or
transfer case, output shaft and remove the propeller
shaft (Fig. 11).
INSTALLATION
(1) Slide the slip yoke on the transmission, or
transfer case, output shaft.
(2) Align the installation reference marks made on
the propeller shaft and pinion yoke.
(3) Position universal joint into pinion yoke.
(4) Install the universal joint clamp and clamp
bolts to the pinion yoke. Tighten bolts to 19 N´m (14
ft. lbs.).
(5) Lower the vehicle.
Fig. 10 FRONT PROPELLER SHAFT - 4.7L
1 - FRONT AXLE
2 - BOOT
3 - PROPELLER SHAFT
4 - DOUBLE CARDAN U-JOINT
5 - TRANSFER CASE
6 - BOOT
7 - SLINGER
8 - CLAMP
9 - YOKE
Fig. 11 REAR PROPELLER SHAFT
1 - SLIDING YOKE
2 - PROPELLER SHAFT
3 - PINION YOKE
4 - CLAMP/STRAP
5 - BOLT
6 - OUTPUT SHAFT
WJPROPELLER SHAFT 3 - 7
PROPELLER SHAFT - FRONT 4.7L (Continued)

BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).²Worn or out-of-balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front±end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear-end
vibration. Do not overlook engine accessories, brack-
ets and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
WJFRONT AXLE - 186FBI 3 - 17
FRONT AXLE - 186FBI (Continued)

Condition Possible Causes Correction
Axle Noise 1. Insufficient lubricant. 1. Fill differential with the correct
fluid type and quantity.
2. Improper ring gear and pinion
adjustment.2. Check ring gear and pinion
contact pattern.
3. Unmatched ring gear and pinion. 3. Replace gears with a matched
ring gear and pinion.
4. Worn teeth on ring gear and/or
pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings. 5. Adjust pinion bearing pre-load.
6. Loose differential bearings. 6. Adjust differential bearing
pre-load.
7. Mis-aligned or sprung ring gear. 7. Measure ring gear run-out.
Replace components as necessary.
8. Loose differential bearing cap
bolts.8. Inspect differential components
and replace as necessary. Ensure
that the bearing caps are torqued
tot he proper specification.
9. Housing not machined properly. 9. Replace housing.
VARI-LOKT
(1) Park the vehicle on a level surface or raise
vehicle on hoist so that the vehicle is level.
(2) Remove the axle fill plug.
(3) Verify that the axle fluid level is correct. The
fluid level is correct if the fluid is level with the bot-
tom of the fill hole.
(4) Shift the transfer case into the 4WD full-time
position.
(5) Drive the vehicle in a tight circle for 2 minutes
at 5mph to fully prime the pump.
(6) Block the tires opposite the axle to be tested to
prevent the vehicle from moving.
(7) Shift the transfer case into the 4WD Low posi-
tion and the transmission into the Park position.
(8) Raise both the wheels of the axle to be tested
off of the ground.
(9) Rotate the left wheel by hand at a minimum of
one revolution per second while an assistant rotates
the right wheel in the opposite direction.
(10) The left wheel should spin freely at first and
then increase in resistance within 5 revolutions until
the wheels cannot be continuously rotated in opposite
directions.
(11) The Vari-loktdifferential has engaged prop-
erly if the wheels cannot be rotated in opposite direc-
tions for a moment. After the wheels stop rotating for
a moment, the fluid pressure will drop in the differ-
ential and the wheels begin to rotate once again.
(12) If the system does not operate properly,
replace the Vari-loktdifferential.
REMOVAL
(1) Raise and support the vehicle.
(2) Position a suitable lifting device under the
axle.
(3) Secure axle to lift.
(4) Remove the wheels and tires.
(5) Remove the brake calipers and rotors (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/ROTORS
- REMOVAL) from the axle.
(6) Disconnect the wheel sensor wiring harness
from the vehicle wiring harness.
(7) Disconnect the vent hose from the axle shaft
tube.
(8) Mark propeller shaft and yoke/pinion flange for
installation alignment reference.
(9) Remove propeller shaft.
(10) Disconnect stabilizer bar links at the axle.
(11) Disconnect shock absorbers from axle brack-
ets.
(12) Disconnect track bar.
(13) Disconnect the tie rod and drag link from the
steering knuckle.
(14) Disconnect the steering damper from the axle
bracket.
(15) Disconnect the upper and lower suspension
arms from the axle brackets.
(16) Lower the lifting device enough to remove the
axle. The coil springs will drop with the axle.
(17) Remove the coil springs from the axle.
3 - 20 FRONT AXLE - 186FBIWJ
FRONT AXLE - 186FBI (Continued)

REAR AXLE - 198RBI
TABLE OF CONTENTS
page page
REAR AXLE - 198RBI
DESCRIPTION.........................50
OPERATION...........................50
DIAGNOSIS AND TESTING................51
REMOVAL.............................55
INSTALLATION.........................56
ADJUSTMENTS........................56
SPECIFICATIONS.......................65
SPECIAL TOOLS.......................66
AXLE SHAFTS
REMOVAL.............................69
INSTALLATION.........................69
AXLE BEARINGS/SEALS
REMOVAL.............................69
INSTALLATION.........................70
PINION SEAL
REMOVAL.............................71
INSTALLATION.........................71
COLLAPSIBLE SPACER
REMOVAL.............................73INSTALLATION.........................73
DIFFERENTIAL
REMOVAL.............................75
DISASSEMBLY.........................77
ASSEMBLY............................77
INSTALLATION.........................77
DIFFERENTIAL-TRAC-LOC
DIAGNOSIS AND TESTING................79
DISASSEMBLY.........................79
CLEANING............................82
INSPECTION..........................82
ASSEMBLY............................82
DIFFERENTIAL CASE BEARINGS
REMOVAL.............................83
INSTALLATION.........................84
PINION GEAR/RING GEAR
REMOVAL.............................84
INSTALLATION.........................86
REAR AXLE - 198RBI
DESCRIPTION
The Rear Beam-design Iron (RBI) axle housing has
an iron center casting with axle shaft tubes extend-
ing from either side. The tubes are pressed into and
welded to the differential housing to form a one-piece
axle housing. The axles has semi-floating axle shafts,
meaning that loads are supported by the axle shaft
and bearings. The axle shafts are retained by bearing
retainer plates on the axles which are bolted to
flanges at the outboard end of the axle tubes.
The differential case is a one-piece design. Differ-
ential bearing preload and ring gear backlash is
adjusted by the use of selective spacer shims. Pinion
bearing preload is set and maintained by the use of a
collapsible spacer. A differential cover provides a
means for inspection and service.
Axles with optional Trac-Loktdifferential have a
one-piece differential case, and the same internal
components as a standard differential, plus two
clutch disc packs.
OPERATION
The axle receives power from the transmission/
transfer case through the rear propeller shaft. Therear propeller shaft is connected to the pinion gear
which rotates the differential through the gear mesh
with the ring gear bolted to the differential case. The
engine power is transmitted to the axle shafts
through the pinion mate and side gears. The side
gears are splined to the axle shafts.
STANDARD DIFFERENTIAL
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 1).
When turning corners, the outside wheel must
travel a greater distance than the inside wheel to
complete a turn. The difference must be compensated
for to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential
allows the axle shafts to turn at unequal speeds (Fig.
2). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
now rotate around the pinion mate shaft in opposite
directions. This allows the side gear and axle shaft
attached to the outside wheel to rotate at a faster
speed.
3 - 50 REAR AXLE - 198RBIWJ

peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side±gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).
²Worn or out-of-balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rearend vibra-
tion. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
3 - 52 REAR AXLE - 198RBIWJ
REAR AXLE - 198RBI (Continued)

Condition Possible Causes Correction
Axle Noise 1. Insufficient lubricant. 1. Fill differential with the correct
fluid type and quantity.
2. Improper ring gear and pinion
adjustment.2. Check ring gear and pinion
contact pattern.
3. Unmatched ring gear and pinion. 3. Replace gears with a matched
ring gear and pinion.
4. Worn teeth on ring gear and/or
pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings. 5. Adjust pinion bearing pre-load.
6. Loose differential bearings. 6. Adjust differential bearing
pre-load.
7. Mis-aligned or sprung ring gear. 7. Measure ring gear run-out.
Replace components as necessary.
8. Loose differential bearing cap
bolts.8. Inspect differential components
and replace as necessary. Ensure
that the bearing caps are torqued
tot he proper specification.
9. Housing not machined properly. 9. Replace housing.
VARI-LOKT
(1) Park the vehicle on a level surface or raise
vehicle on hoist so that the vehicle is level.
(2) Remove the axle fill plug.
(3) Verify that the axle fluid level is correct. The
fluid level is correct if the fluid is level with the bot-
tom of the fill hole.
(4) Shift the transfer case into the 4WD full-time
position.
(5) Drive the vehicle in a tight circle for 2 minutes
at 5mph to fully prime the pump.
(6) Block the tires opposite the axle to be tested to
prevent the vehicle from moving.
(7) Shift the transfer case into the 4WD Low posi-
tion and the transmission into the Park position.
(8) Raise both the wheels of the axle to be tested
off of the ground.
(9) Rotate the left wheel by hand at a minimum of
one revolution per second while an assistant rotates
the right wheel in the opposite direction.
(10) The left wheel should spin freely at first and
then increase in resistance within 5 revolutions until
the wheels cannot be continuously rotated in opposite
directions.
(11) The Vari-loktdifferential has engaged prop-
erly if the wheels cannot be rotated in opposite direc-tions for a moment. After the wheels stop rotating for
a moment, the fluid pressure will drop in the differ-
ential and the wheels begin to rotate once again.
(12) If the system does not operate properly,
replace the Vari-loktdifferential.
REMOVAL
(1) Raise and support the vehicle.
(2) Position a lifting device under the axle and
secure axle.
(3) Remove the wheels and tires.
(4) Remove brake calipers and rotors.
(5) Disconnect parking brake cables from brackets
and lever.
(6) Remove wheel speed sensors.
(7) Remove brake hose at the axle junction block.
Do not disconnect the brake hydraulic lines at the
calipers.
(8) Disconnect the vent hose from the axle shaft
tube.
(9) Mark propeller shaft and yokes for installation
reference.
(10) Remove propeller shaft.
(11) Disconnect stabilizer bar links.
(12) Remove upper suspension arm rear axle ball
joint nut.
WJREAR AXLE - 198RBI 3 - 55
REAR AXLE - 198RBI (Continued)

AXLE SHAFTS
REMOVAL
(1) Place transmission in neutral.
(2) Raise and support vehicle.
(3) Remove wheel and tire assembly.
(4) Remove brake caliper and rotor.
(5) Remove nuts holding axle retainer plate to axle
tube from the rear of the axle flange.
(6) Pull axle shaft from the axle with Slide Ham-
mer 7420 and Adapter 6790. Mount the adapter to
the axle with lug nuts.
NOTE: The axle bearing race is normally loose in
the axle tube.
INSTALLATION
(1) Insall axle into the axle tube with the flat area
of the retainer plate upward.
(2) Insert retaining plate studs into the brake
backing plate and axle tube flange.
(3) Install retainer nuts and tighten nuts to 61
N´m (45 ft. lbs.).
(4) Install the brake rotor and caliper.
(5) Install wheel and tire.
(6) Check and fill the differential with gear lubri-
cant.
(7) Lower vehicle.
AXLE BEARINGS/SEALS
REMOVAL
(1) Remove axle shaft from vehicle.
NOTE: The axle bearing race is normally loose in
the axle tube.
(2) Drill a shallow hole into soft steel axle bearing
retaining ring with a 3/8 in. drill bit (Fig. 25). Use a
drill depth stop to avoid marking the axle.
(3) With a cold chisel cut the retaining ring across
drilled hole. (Fig. 26)
(4) Slide retaining ring from axle shaft.
Fig. 25 DRILL RETAINING RING
1 - DRILL BIT
2 - AXLE
3 - RETAINING PLATE
4 - RETAINING RING
Fig. 26 RETAINING RING
1 - AXLE
2 - COLD CHISEL
3 - VISE
4 - RETAINING RING
WJREAR AXLE - 198RBI 3 - 69