2002 JEEP LIBERTY wheel

(6) Using yoke with Spanner Wrench 6958 and a
torque wrench set at 474 N´m (350 ft. lbs.), (Fig. 41)
slowly tighten the nut in 6.8 N´m (5 ft. lbs.) incre-
ments until the rotating torque is achieved. Measure
the rotating torque frequently to avoid over crushing
the collapsible spacer (Fig. 42).
NOTE: If more than 474 N´m (350 ft. lbs.) torque is
required to crush the collapsible spacer, the spacer
is defective and must be replaced.
(7) Check rotating torque with an inch pound
torque wrench (Fig. 42). The rotating torque of the
pinion gear should be, the reading recorded during
removal plus an additional 0.56 N´m (5 in. lbs.).
(8) Install propeller shaft with reference marks
aligned.
(9) Install rear brake drums.
(10) Add gear lubricant, if necessary.
(11) Install wheel and tire assemblies.
(12) Remove supports and lower vehicle.
DIFFERENTIAL
REMOVAL
(1) Raise and support vehicle.
(2) Remove differential cover and drain fluid.
(3) Clean the housing cavity with flushing oil, light
engine oil or lint free cloth.NOTE: Do not use water, steam, kerosene or gaso-
line for cleaning.
(4) Remove axle shafts.
(5)
Note the reference letters stamped on the bearing
caps and housing machined sealing surface (Fig. 43).
Fig. 41 YOKE SPANNER WRENCH
1 - PINION YOKE
2 - WRENCH
3 - PIPE
Fig. 42 PINION ROTATING TORQUE
1 - TORQUE WRENCH
2 - PINION YOKE
Fig. 43 BEARING CAP IDENTIFICATION
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
KJREAR AXLE - 198RBI 3 - 71
COLLAPSIBLE SPACER (Continued)

(6) Install the bearing caps in their original loca-
tions (Fig. 50).
(7) Loosely install differential bearing cap bolts.
(8) Remove axle housing spreader.
(9) Tighten the bearing cap bolts to 64-91 N´m
(47-67 ft. lbs.).
(10) Install the axle shafts.
(11) Apply a 6.35mm (1/4 in.) bead of red Mopar
Silicone Rubber Sealant or equivalent to the housing
cover (Fig. 51).
CAUTION: If cover is not installed within 3 to 5 min-
utes, the cover must be cleaned and new RTV
applied or adhesion quality will be compromised.
(12) Install the cover and tighten cover bolts in a
criss-cross pattern to 38-45 N´m (28-33 ft. lbs.).
(13) Refill the differential with lubricant and
install fill plug.
(14) Remove support and lower the vehicle.
DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING - TRAC-LOKT
The most common problem is a chatter noise when
turning corners. Before removing the unit for repair,
drain, flush and refill the axle with the specified
lubricant. A container of Mopar Trac-loktLubricant
(friction modifier) should be added after repair ser-
vice or during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
DIFFERENTIAL TEST
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.
(4) Remove wheel and bolt Special Tool 6790 or
equivalent tool to studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 52).
(6) If rotating torque is less than 41 N´m (56 ft.
lbs.) or more than 271 N´m (200 ft. lbs.) on either
wheel the unit should be serviced.
Fig. 50 BEARING CAP REFERENCE
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
Fig. 51 DIFFERENTIAL COVER - TYPICAL
1 - SEALING SURFACE
2 - SEALANT BEAD
3 - SEALANT THICKNESS
3 - 74 REAR AXLE - 198RBIKJ
DIFFERENTIAL (Continued)

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.
TRAC-LOKTDIFFERENTIAL
This differentials clutches are engaged by two con-
current forces. The first being the preload force
exerted through Belleville spring washers within the
clutch packs. The second is the separating forces gen-
erated by the side gears as torque is applied through
the ring gear (Fig. 3).
This design provides the differential action needed
for turning corners and for driving straight ahead
during periods of unequal traction. When one wheel
looses traction, the clutch packs transfer additional
torque to the wheel having the most traction. This
differential resist wheel spin on bumpy roads and
provide more pulling power when one wheel looses
Fig. 1 Differential Operation - Straight Ahead Driving
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 2 Differential Operation - On Turns
1 - PINION GEARS ROTATE ON PINION SHAFT
Fig. 3 Trac-lokTLimited Slip Differential
1 - CASE
2 - RING GEAR
3 - DRIVE PINION
4 - PINION GEAR
5 - MATE SHAFT
6 - CLUTCH PACK
7 - SIDE GEAR
8 - CLUTCH PACK
KJREAR AXLE - 8 1/4 3 - 87
REAR AXLE - 8 1/4 (Continued)

traction. Pulling power is provided continuously until
both wheels loose traction. If both wheels slip due to
unequal traction, Trac-lokŸ operation is normal. In
extreme cases of differences of traction, the wheel
with the least traction may spin.
DIAGNOSIS AND TESTING - AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, incorrect pinion depth, tooth
contact, worn/damaged gears, or the carrier housing
not having the proper offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
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 shaft can also cause a snap-
ping 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 changeswhen 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.
NOTE: All driveline components should be exam-
ined before starting any repair.
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 - 88 REAR AXLE-81/4KJ
REAR AXLE - 8 1/4 (Continued)

DIAGNOSTIC CHART
Condition Possible Causes Correction
Wheel Noise 1. Wheel loose. 1. Tighten loose nuts.
2. Faulty, brinelled wheel bearing. 2. Replace bearing.
Axle Shaft Noise 1. Misaligned axle tube. 1. Inspect axle tube alignment.
Correct as necessary.
2. Bent or sprung axle shaft. 2. Inspect and correct as necessary.
Axle Shaft Broke 1. Misaligned axle tube. 1. Replace the broken shaft after
correcting tube mis-alignment.
2 Vehicle overloaded. 2. Replace broken shaft and avoid
excessive weight on vehicle.
3. Erratic clutch operation. 3. Replace broken shaft and avoid
or correct erratic clutch operation.
4. Grabbing clutch. 4. Replace broken shaft and inspect
and repair clutch as necessary.
Differential Cracked 1. Improper adjustment of the
differential bearings.1. Replace case and inspect gears
and bearings for further damage.
Set differential bearing pre-load
properly.
2. Excessive ring gear backlash. 2. Replace case and inspect gears
and bearings for further damage.
Set ring gear backlash properly.
3. Vehicle overloaded. 3. Replace case and inspect gears
and bearings for further damage.
Avoid excessive vehicle weight.
4. Erratic clutch operation. 4. Replace case and inspect gears
and bearings for further damage.
Avoid erratic use of clutch.
Differential Gears Scored 1. Insufficient lubrication. 1. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
2. Improper grade of lubricant. 2. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
3. Excessive spinning of one
wheel/tire.3. Replace scored gears. Inspect all
gears, pinion bores, and shaft for
damage. Service as necessary.
KJREAR AXLE - 8 1/4 3 - 89
REAR AXLE - 8 1/4 (Continued)

REMOVAL
(1) Raise and support the vehicle.
(2) Position a lift/jack under the axle and secure
axle to device.
(3) Remove wheels and tires.
(4) Mark propeller shaft and pinion yoke for
installation reference.
(5) Remove propeller shaft and suspend under the
vehicle.
(6) Remove brake drums, parking brake cables and
speed sensor from the axle.
(7) Disconnect the brake hose at the body junction
block.
(8) Remove brakes and backing plates.
(9) Remove vent hose from the axle shaft tube.
(10) Remove the stabilizer bar (Fig. 4).
(11) Remove upper control arm ball joint pinch
bolt from bracket (Fig. 5).
(12) Remove shock absorbers from axle brackets
(Fig. 6).
(13) Loosen all lower control arms mounting bolts
(Fig. 7).
(14) Lower axle enough to remove coil springs and
spring insulators.
(15) Remove lower control arm bolts from the axle
brackets.
(16) Lower and remove the axle.
INSTALLATION
CAUTION: The weight of the vehicle must be sup-
ported by the springs before the lower control arms
are tightened. This must be done to maintain vehi-
cle ride height and prevent premature bushing fail-
ure.(1) Raise the axle under the vehicle.
(2) Install lower control arms onto the axle brack-
ets and loosely install the mounting bolts.
(3) Install coil spring isolators and spring.
(4) Raise axle up until springs are seated.
(5) Install upper control arm ball joint into axle
bracket and tighten pinch bolt to torque specification.
(6) Install shock absorbers and tighten nuts to
torque specification.
(7) Install stabilizer bar and tighten nuts to torque
specification.
(8) Install brake backing plates, parking brake
cables, brake drums and speed sensor.
(9) Install brake hose to the body junction block
and bleed the brakes.
Fig. 4 STABILIZER BAR MOUNTS
1 - STABILIZER BAR MOUNTING BOLTS
2 - LOWER SUSPENSION ARM
Fig. 5 BALL JOINT PINCH BOLT
1 - UPPER BALL JOINT
2 - PINCH BOLT
Fig. 6 SHOCK ABSORBER
1 - UPPER MOUNTING BOLT
2 - LOWER MOUNTING BOLT
KJREAR AXLE - 8 1/4 3 - 91
REAR AXLE - 8 1/4 (Continued)

(10) Install axle vent hose.
(11) Install propeller shaft with reference marks.
(12) Install the wheels and tires.
(13) Add gear lubricant to specifications, if neces-
sary.
(14) Remove lifting device from axle and lower the
vehicle.
(15) Tighten the lower control arm bolts to torque
specification.
ADJUSTMENTS
Ring gears and pinions are supplied as matched
sets only. The identifying numbers for the ring gear
and pinion are etched/marked onto each gear (Fig. 8).
A plus (+) number, minus (±) number or zero (0) is
etched/marked on the face or shaft of the pinion. This
number is the amount (in thousandths of an inch)
the depth varies from the standard depth setting of a
pinion etched with a (0). The standard depth pro-
vides the best gear tooth contact pattern. Refer to
Backlash and Contact Pattern Analysis paragraph in
this section for additional information.
Compensation for pinion depth variance is
achieved with select shims. The shims are placed
behind the rear pinion bearing (Fig. 9).
If a new gear set is being installed, note the depth
variance etched into both the original and replace-
ment pinion. Add or subtract the thickness of the
original depth shims to compensate for the difference
in the depth variances. Refer to the Depth Variance
chart.
Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or
minus the amount needed.Note the etched number on the face of the pinion
gear head (±1, ±2, 0, +1, +2, etc.). The numbers rep-
resent thousands of an inch deviation from the stan-
dard. If the number is negative, add that value to the
required thickness of the depth shims. If the number
is positive, subtract that value from the thickness of
the depth shim. If the number is 0 no change is nec-
essary.
Fig. 7 LOWER SUSPENSION ARM
1 - AXLE BRACKET BOLT
2 - LOWER CONTROL ARM
3 - BODY BRACKET BOLT
Fig. 8 Pinion Gear ID Numbers - Typical
1 - PRODUCTION NUMBERS
2 - DRIVE PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER (SAME AS RING GEAR
NUMBER)
Fig. 9 Adjustment Shim Locations
1 - DIFFERENTIAL HOUSING
2 - COLLAPSIBLE SPACER
3 - REAR PINION BEARING
4 - PINION DEPTH SHIM
5 - PINION GEAR
6 - BEARING CUP
3 - 92 REAR AXLE-81/4KJ
REAR AXLE - 8 1/4 (Continued)

AXLE SHAFTS
REMOVAL
(1) Place the transmission in NEUTRAL and raise
and support vehicle.
(2) Remove wheel and tire assembly.
(3) Remove brake drum.
(4) Remove the housing cover and drain lubricant.
(5) Rotate differential case to access the pinion
shaft lock screw. Remove lock screw and pinion shaft
from differential case (Fig. 19).
(6) Push axle shaft inward then remove axle shaft
C-lock (Fig. 20).(7) Remove axle shaft being carefull not to damage
shaft bearing and seal.
(8) Inspect axle shaft seal for leakage or damage.
(9) Inspect axle shaft bearing contact surface for
signs of brinelling, galling and pitting.
INSTALLATION
(1) Lubricate bearing bore and seal lip with gear
lubricant. Insert axle shaft through seal, bearing and
engage it into side gear splines.
NOTE: Use care to prevent shaft splines from dam-
aging axle shaft seal lip.
(2) Insert C-lock in end of axle shaft. Push axle
shaft outward to seat C-lock in side gear.
(3) Insert pinion shaft into differential case and
through thrust washers and differential pinions.
(4) Align hole in shaft with hole in the differential
case and install lock screw with Loctiteton the
threads. Tighten lock screw to 11 N´m (8 ft. lbs.).
(5) Install cover and fill with gear lubricant to the
bottom of the fill plug hole.
(6) Install brake drum.
(7) Install wheel and tire assemblies.
(8) Remove support and lower vehicle.
AXLE SHAFT SEALS
REMOVAL
(1) Raise and support vehicle.
(2) Remove axle shaft.
(3) Remove axle shaft seal from the axle tube with
a small pry bar (Fig. 21).
Fig. 19 Pinion Shaft Lock Screw
1 - LOCK SCREW
2 - PINION SHAFT
Fig. 20 Axle Shaft C-Lock
1 - C-LOCK
2 - AXLE SHAFT
3 - SIDE GEARFig. 21 Axle Seal
1 - AXLE TUBE
2 - AXLE SEAL
3-PRYBAR
KJREAR AXLE - 8 1/4 3 - 101