Turn JEEP LIBERTY 2002 KJ / 1.G Owner's Manual

(6) Loosen the differential bearing cap bolts.
(7) With Spreader W-129-B and adapters from
Adapter set 6987, position the adapters in the differ-
ential holes (Fig. 44). Install hold-down clamps and
tighten the tool turnbuckle finger-tight.
(8) Install Pilot Stud C-3288-B at the left side of
the differential housing. Attach Dial Indicator C-3339
to pilot stud. Load the indicator plunger against the
opposite side of the housing (Fig. 45) and zero the
indicator.
(9) Spread the housing while measuring the dis-
tance with the dial indicator. Spread the housing
enough to remove the differential case (Fig. 46).
CAUTION: Do not spread over 0.38 mm (0.015 in). If
housing is over-spread, it could be distorted or
damaged.
(10) Remove the dial indicator and pilot stud.
(11) Remove differential bearing cap bolts and caps
while holding the case.
Fig. 44 SPREADER LOCATION
1 - DIFFERENTIAL HOUSING
2 - ADAPTER
3 - SAFETY HOLD DOWN
4 - SPREADER
5 - TURNBUCKLE
Fig. 45 DIAL INDICATOR LOCATION
1 - CLAMP
2 - DIAL INDICATOR
3 - LEVER ADAPTER
4 - SPREADER
5 - PILOT STUD
Fig. 46 SPREAD DIFFERENTIAL HOUSING
1 - DIAL INDICATOR
2 - SPREADER
3 - 72 REAR AXLE - 198RBIKJ
DIFFERENTIAL (Continued)

(12) Remove differential from the housing. Ensure
that the differential bearing cups remain in position
on the differential bearings (Fig. 47).
(13) Remove bearing cups from the differential and
tag them to indicate their location.
(14) Remove differential case preload shims from
the housing and tag them to indicate their location.
(15) Remove spreader from housing.
INSTALLATION
NOTE: If differential bearings or differential case are
replaced, differential bearing preload shim require-
ments may change. Refer Adjustments (Differential
Bearing Preload and Gear Backlash) to determine
the proper shim selection.
(1) With Spreader W-129-B and adapters from
Adapter set 6987, position the adapters in the differ-
ential holes (Fig. 48). Install the hold-down clamps
and tighten the tool turnbuckle finger-tight.
(2) Install a Pilot Stud C-3288-B at the left side of
the differential housing. Attach Dial Indicator C-3339
to pilot stud. Load the indicator plunger against the
opposite side of the housing and zero the indicator.
(3) Spread the housing while measuring the dis-
tance with the dial indicator. Spread the housing
enough to install the differential case.
CAUTION: Do not spread over 0.38 mm (0.015 in). If
the housing is over±spread, it could be distorted or
damaged.
(4) Remove the dial indicator.(5) Install differential case in the housing (Fig. 49)
with bearing cups and preload shims in their original
locations. Tap the differential case to ensure the
bearings cups and shims are fully seated in the hous-
ing.
Fig. 47 DIFFERENTIAL CASE
1 - DIFFERENTIAL HOUSING
2 - DIFFERENTIAL CASE
3 - BEARING CUPSFig. 48 SPREADER LOCATION
1 - DIFFERENTIAL HOUSING
2 - ADAPTER
3 - SAFETY HOLD DOWN
4 - SPREADER
5 - TURNBUCKLE
Fig. 49 DIFFERENTIAL CASE
1 - DIFFERENTIAL HOUSING
2 - DIFFERENTIAL CASE
3 - BEARING CUPS
KJREAR AXLE - 198RBI 3 - 73
DIFFERENTIAL (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)

(6) Assemble Threaded Adapter 6960-1 into top
side gear. Thread Forcing Screw C-6960-4 into
adapter until it becomes centered in adapter plate.
(7) Position a small screw driver in slot of
Threaded Adapter Disc 6960-3 (Fig. 56) to prevent
adapter from turning.
(8) Install Forcing Screw 6960-4 and tighten screw
to 122 N´m (90 ft. lbs.) maximum to compress
Belleville springs in clutch packs (Fig. 57).
(9) With a feeler gauge remove thrust washers
from behind the pinion gears (Fig. 58).
Fig. 56 THREAD ADAPTER DISC
1 - SOCKET
2 - SLOT IN ADAPTER
3 - SCREWDRIVER
4 - STEP PLATE
5 - THREADED ROD
6 - ADAPTER DISC
Fig. 57 COMPRESS BELLEVILLE SPRING
1 - TORQUE WRENCH
2 - FORCING SCREW
3 - DIFFERENTIAL CASE
Fig. 58 PINION GEAR THRUST WASHER
1 - THRUST WASHER
2 - FEELER GAUGE
3 - 76 REAR AXLE - 198RBIKJ
DIFFERENTIAL - TRAC-LOK (Continued)

(10) Insert Turning Bar 6960-2 into the pinion
mate shaft hole in the case (Fig. 59).
(11) Loosen the Forcing Screw in small increments
until the clutch pack tension is relieved and the dif-
ferential case can be turned using Turning Bar.
(12) Rotate differential case until the pinion gears
can be removed.
(13) Remove pinion gears from differential case.
(14) Remove Forcing Screw, Step Plate and
Threaded Adapter.
(15) Remove top side gear, clutch pack retainer
and clutch pack. Keep plates in order during removal
(Fig. 60).
(16) Remove differential case from the Holding
Fixture. Remove side gear, clutch pack retainer and
clutch pack. Keep plates in order during removal.
CLEANING
Clean all components in cleaning solvent and dry
components with compressed air.
INSPECTION
Inspect clutch pack plates for wear, scoring or dam-
age. Replace both clutch packs if any one component
in either pack is damaged. Inspect side and pinion
gears for cracks chips or damage and replace as nec-
essary. Inspect differential case and pinion shaft and
replace if worn or damaged.
ASSEMBLY
NOTE: New Plates and discs with fiber coating (no
grooves or lines) must be presoaked in Friction
Modifier before assembly. Soak plates and discs for
a minimum of 20 minutes.(1) Lubricate components with gear lubricant.
(2) Assemble clutch discs into packs and secure
disc packs with retaining clips (Fig. 61).
NOTE: Dished plate is position with the convex side
against the side gear.
Fig. 59 PINION GEARS
1 - PINION GEARS
2 - TURNING BAR
Fig. 60 SIDE GEARS AND CLUTCH DISCS
1 - DIFFERENTIAL CASE
2 - RETAINER
3 - SIDE GEAR AND CLUTCH DISC PACK
Fig. 61 CLUTCH PACK
1 - DISCS
2 - DISHED PLATE
3 - RETAINER
4 - SIDE GEAR
5 - RETAINER
6 - PLATES
KJREAR AXLE - 198RBI 3 - 77
DIFFERENTIAL - TRAC-LOK (Continued)

(3) Position assembled clutch disc packs on the
side gear hubs.
(4) Install clutch pack and side gear in the ring
gear side of the differential case (Fig. 62).Verify
clutch pack retaining clips are in position and
seated in the case pockets.
(5) Position the differential case on the Holding
Fixture 6965.
(6) Install lubricated Step Plate 6960-3 in lower
side gear (Fig. 63).
(7) Install the upper side gear and clutch disc pack
(Fig. 63).
(8) Hold assembly in position. Insert Threaded
Adapter 6960-1 into top side gear.
(9) Install Forcing Screw 6960-4 and tighten screw
to slightly compress clutch disc.
(10) Place pinion gears in position in side gears
and verify that the pinion mate shaft hole is aligned.(11) Rotate case with Turning Bar 6960-2 until the
pinion mate shaft holes in pinion gears align with
holes in case. It may be necessary to slightly tighten
the forcing screw in order to install the pinion gears.
(12) Tighten forcing screw to 122 N´m (90 ft. lbs.)
maximum to compress the Belleville springs.
(13) Lubricate and install thrust washers behind
pinion gears and align washers with a small screw
driver. Insert mate shaft into each pinion gear to ver-
ify alignment.
(14) Remove Forcing Screw, Step Plate and
Threaded Adapter.
(15) Install pinion gear mate shaft and align holes
in shaft and case.
(16) Install pinion mate shaft lock screw finger
tight to hold shaft during differential installation.
(17) Lubricate all differential components with
hypoid gear lubricant.
Fig. 62 CLUTCH PACK AND LOWER SIDE GEAR
1 - DIFFERENTIAL CASE
2 - SIDE GEAR AND CLUTCH PACK
Fig. 63 CLUTCH PACK AND UPPER SIDE GEAR
1 - SIDE GEAR AND CLUTCH PACK
2 - DIFFERENTIAL CASE
3 - STEP PLATE
3 - 78 REAR AXLE - 198RBIKJ
DIFFERENTIAL - TRAC-LOK (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)

(6) Position Scooter Block/Dial Indicator flush on
the pinion height block. Hold scooter block and zero
the dial indicator.
(7) Slowly slide the scooter block across the pinion
height block over to the arbor (Fig. 13). Move the
scooter block till the dial indicator probe crests the
arbor, then record the highest reading.
(8) Select a shim equal to the dial indicator read-
ing plus the drive pinion gear depth variance number
etched/marked on the pinion (Fig. 8). For example, if
the depth variance is ±2, add +0.002 in. to the dial
indicator reading.
BEARING PRELOAD AND GEAR BACKLASH
The following must be considered when adjusting
bearing preload and gear backlash:
²The maximum ring gear backlash variation is
0.076 mm (0.003 inch).
²Mark the gears so the same teeth are meshed
during all backlash measurements.
²Maintain the torque while adjusting the bearing
preload and ring gear backlash.
²Excessive adjuster torque will introduce a high
bearing load and cause premature bearing failure.
Insufficient adjuster torque can result in excessive
differential case free-play and ring gear noise.
²Insufficient adjuster torque will not support the
ring gear correctly and can cause excessive differen-
tial case free-play and ring gear noise.
NOTE: The differential bearing cups will not always
immediately follow the threaded adjusters as they
are moved during adjustment. To ensure accurate
bearing cup responses to the adjustments:
²Maintain the gear teeth engaged (meshed) as
marked.
²The bearings must be seated by rapidly rotat-
ing the pinion gear a half turn back and forth.
²Do this five to ten times each time the threaded
adjusters are adjusted.
(1) Adjust each threaded adjuster inward with
Wrench C-4164 until the differential bearing free-
play is eliminated (Fig. 14). Allow some ring gear
backlash, approximately 0.25 mm (0.01 in.) between
the ring and pinion gear. Seat the bearing cups with
the procedure described above.
Fig. 12 Gauge Tools In Housing
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
Fig. 13 Pinion Gear Depth Measurement
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
Fig. 14 Threaded Adjuster
1 - AXLE TUBE
2 - BACKING PLATE
3 - ADJUSTER WRENCH
3 - 94 REAR AXLE-81/4KJ
REAR AXLE - 8 1/4 (Continued)

(2) Install dial indicator and position the plunger
against the drive side of a ring gear tooth (Fig. 15).
Measure the backlash at 4 positions (90 degrees
apart) around the ring gear. Locate and mark the
area of minimum backlash.
(3) Rotate the ring gear to the position of the least
backlash. Mark the gear so that all future backlash
measurements will be taken with the same gear
teeth meshed.
(4) Loosen the right-side, tighten the left-side
threaded adjuster. Obtain backlash of 0.076 to 0.102
mm (0.003 to 0.004 in.) with each adjuster tightened
to 14 N´m (10 ft. lbs.). Seat the bearing cups with the
procedure described above.
(5) Tighten the differential bearing cap bolts in a
criss-cross pattern to 95 N´m (70 ft. lbs.).
(6) Tighten the right-side threaded adjuster to 102
N´m (75 ft. lbs.). Seat the bearing cups with the pro-
cedure described above. Continue to tighten the
right-side adjuster and seat bearing cups until the
torque remains constant at 102 N´m (75 ft. lbs.)(7) Measure the ring gear backlash. The range of
backlash is 0.15 to 0.203 mm (0.006 to 0.008 in.).
(8) Continue increasing the torque at the right-
side threaded adjuster until the specified backlash is
obtained.
NOTE: The left-side threaded adjuster torque
should have approximately 102 N´m (75 ft. lbs.). If
the torque is considerably less, the complete
adjustment procedure must be repeated.
(9) Tighten the left-side threaded adjuster until
102 N´m (75 ft. lbs.) torque is indicated. Seat the
bearing rollers with the procedure described above.
Do this until the torque remains constant.
(10) Install the threaded adjuster locks and
tighten the lock screws to 10 N´m (90 in. lbs.).
After the proper backlash is achieved, perform the
Gear Contact Pattern procedure.
GEAR CONTACT PATTERN
The ring gear and pinion teeth contact patterns
will show if the pinion depth is correct in the hous-
ing. It will also show if the ring gear backlash has
been adjusted correctly. The backlash can be adjusted
within specifications to achieve desired tooth contact
patterns.
(1) Apply a thin coat of hydrated ferric oxide or
equivalent, to the drive and coast side of the ring
gear teeth.
(2) Wrap, twist and hold a shop towel around the
pinion yoke to increase the turning resistance of the
pinion. This will provide a more distinct contact pat-
tern.
(3) With a boxed end wrench on a ring gear bolt,
rotate the differential case one complete revolution in
both directions while a load is being applied from
shop towel.
The areas on the ring gear teeth with the greatest
degree of contact against the pinion teeth will squee-
gee the compound to the areas with the least amount
of contact. Note and compare patterns on the ring
gear teeth to Gear Tooth Contact Patterns chart (Fig.
16) and adjust pinion depth and gear backlash as
necessary.
Fig. 15 Ring Gear Backlash
1 - DIAL INDICATOR
2 - RING GEAR
3 - EXCITER RING
KJREAR AXLE - 8 1/4 3 - 95
REAR AXLE - 8 1/4 (Continued)