Control JEEP GRAND CHEROKEE 2002 WJ / 2.G User Guide

REAR
TABLE OF CONTENTS
page page
REAR
DESCRIPTION.........................17
WARNING.............................17
DIAGNOSIS AND TESTING - REAR
SUSPENSION........................18
SPECIFICATIONS
TORQUE CHART......................18
SPECIAL TOOLS
REAR SUSPENSION...................19
LOWER CONTROL ARM
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
SHOCK
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
SPRING
DESCRIPTION.........................20OPERATION...........................20
REMOVAL.............................20
INSTALLATION.........................20
STABILIZER BAR
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................21
UPPER BALL JOINT
DESCRIPTION - UPPER SUSPENSION ARM,
BUSHINGS, AND BALL JOINT............21
OPERATION - UPPER SUSPENSION ARM,
BUSHINGS, AND BALL JOINT............21
REMOVAL.............................21
INSTALLATION.........................22
UPPER CONTROL ARM
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................23
REAR
DESCRIPTION
The rear suspension (Fig. 1) is comprised of :
²Drive axle
²Shock absorbers
²Coil springs
²Lower suspension arms
²Upper suspension arm
²Stabilizer bar
CAUTION: Suspension components with rubber/ure-
thane bushings should be tightened with the vehi-
cle at normal ride height. It is important to have the
springs supporting the weight of the vehicle when
the fasteners are torqued. This will maintain vehicle
ride comfort and prevent premature bushing wear.
WARNING
WARNING:: Suspension components with rubber
bushings must be tightened with the vehicle at nor-
mal ride height. It is important to have the springs
supporting the weight of the vehicle when the fas-
teners are torqued. If springs are not at their normalride position, vehicle ride comfort will be affected
and cause premature bushing wear.
Fig. 1 Rear Suspension
1 - SHOCK
2 - UPPER SUSPENSION ARM
3 - COIL SPRING
4 - STABILIZER BAR
5 - LOWER SUSPENSION ARM
WJREAR 2 - 17

SPECIAL TOOLS
REAR SUSPENSION
LOWER CONTROL ARM
DESCRIPTION
The lower suspension arms are hydroformed steel
and use voided oval bushings at each end of the arm.
OPERATION
The bushings provide isolation from the axle. The
arms mount to the unibody frame rail bracket and
the axle brackets. The arm and bushings provide
location and react to loads.
REMOVAL
(1) Raise the vehicle and support the rear axle.
(2) Remove the lower suspension arm nut and bolt
from the axle bracket (Fig. 2).
(3) Remove the nut and bolt (Fig. 2) from the
frame rail and remove the lower suspension arm.
INSTALLATION
(1) Position the lower suspension arm in the axle
bracket and frame rail bracket.
NOTE: The end of the arm with the oval bushing
attaches to the axle bracket.
(2) Install the axle bracket bolt and nut finger
tight.
(3) Install the frame rail bracket bolt and nut fin-
ger tight.
(4) Remove the supports and lower the vehicle.
(5) With the vehicle on the ground tighten the nut
at the frame to 156 N´m (115 ft. lbs.). Tighten the
nut at the axle bracket to 163 N´m (120 ft. lbs.).
SHOCK
DESCRIPTION
The top of the shock absorbers are bolted to the
body. The bottom of the shocks are bolted to the axle
brackets. The standard shocks have conventional
twin tube construction and are low pressure gas
charged. Gas charging prevents cavitation during
rough road operation. Up-Country shocks are mono
tube design and are high pressure gas charged.
OPERATION
The shock absorbers dampen jounce and rebound
motion of the vehicle over various road conditions
and limit suspension rebound travel.
REMOVAL
(1) Raise and support the vehicle. Position a
hydraulic jack under the axle to support the axle.
CAUTION: Do not allow the axle to hang from the
upper suspension arm ball joint.
(2) Remove the upper nut and bolt from the frame
bracket (Fig. 3).
(3) Remove the lower nut and bolt from the axle
bracket. Remove the shock absorber.
INSTALLATION
(1) Install the shock absorber in the frame bracket
and install the bolt and nut.
(2) Install the shock absorber in the axle bracket
and install the bolt and nut.
(3) Tighten the upper mounting nuts to 108 N´m
(80 ft. lbs.). Tighten the lower mounting nuts to 115
N´m (85 ft. lbs.).
(4) Remove the supports and lower the vehicle.
Remover 8278
Fig. 2 Lower Suspension Arm
1 - LOWER SUSPENSION ARM
2 - AXLE BRACKET
3 - FRAME BRACKET
WJREAR 2 - 19
REAR (Continued)

SPRING
DESCRIPTION
The coil springs mount up in the wheelhouse which
is part of the unitized body bracket. A rubber dough-
nut isolator is located between the top of the spring
and the body. The bottom of the spring seats on a
axle isolator made of rubber with a steel insert. The
isolators provide road noise isolation
OPERATION
The coil springs control ride quality and maintain
proper ride height.
REMOVAL
(1) Raise and support the vehicle. Position a
hydraulic jack under the axle to support the axle.
(2) Remove the wheel and tire assemblies.
(3) Remove the stabilizer bar link from the stabi-
lizer bar (Fig. 4).
(4) Remove the shock absorber lower bolt from the
axle bracket.
(5) Lower the hydraulic jack and tilt the axle and
remove the coil spring (Fig. 4).
(6) Remove and inspect the upper and lower
spring isolators (Fig. 4).
INSTALLATION
(1) Install the upper isolator.
(2) Install the lower isolator with the isolator loca-
tor nub in the axle pad hole (Fig. 5).
(3) Pull down on the axle and position the coil
spring in the lower isolator.CAUTION: Ensure the spring is positioned on the
lower isolator with the end of the spring coil
against the isolator spring locator (Fig. 6).
(4) Raise the axle with the hydraulic jack.
(5) Install the shock absorber to the axle bracket
and tighten to specification.
(6) Install the stabilizer bar link to the stabilizer
bar.
(7) Install the wheel and tire assemblies.
(8) Remove the supports and lower the vehicle.
(9) Tighten the stabilizer bar links to specification.
Fig. 3 Shock Absorber
1 - SHOCKFig. 4 Coil Spring
1 - COIL SPRING
2 - ISOLATOR
3 - STABILIZER LINK
4 - ISOLATOR
Fig. 5 Isolator Locator Nub
1 - LOWER ISOLATOR
2 - LOCATOR NUB
3 - AXLE SPRING PAD
2 - 20 REARWJ
SHOCK (Continued)

STABILIZER BAR
DESCRIPTION
The stabilizer bar extends across the back side of
the rear axle. Links are connected between the bar
and frame rail brackets. The stabilizer bar and links
are isolated by rubber bushings.
OPERATION
The stabilizer bar is used to control vehicle body
roll, during turns. The bar helps control the vehicle
body in relationship to the suspension.
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the stabilizer bar links from stabilizer
bar and frame mount. (Fig. 7).
(3) Remove the stabilizer bar retainer bolts.
(4) Remove the stabilizer bar.
INSTALLATION
(1) Position the stabilizer bar on the axle and
install the retainers and bolts. Ensure the bar is cen-
tered with equal spacing on both sides. Tighten the
bolts to 54 N´m (40 ft. lbs.).
(2) Install the links to the stabilizer bar and frame
brackets.
(3) Tighten the nuts at the stabilizer bar to 54
N´m (40 ft. lbs.).
(4) Tighten the nuts at the frame brackets to 92
N´m (68 ft. lbs.).
(5) Remove support and lower the vehicle.
UPPER BALL JOINT
DESCRIPTION - UPPER SUSPENSION ARM,
BUSHINGS, AND BALL JOINT
The suspension arm uses vertical spool bushings to
isolate road noise. The suspension arm is bolted
through bushings to cage nuts in the body and a ball
joint plate to the top of the differential housing.
OPERATION - UPPER SUSPENSION ARM,
BUSHINGS, AND BALL JOINT
The upper suspension arm provides fore/aft and
lateral location of the rear axle. The suspension arm
travel is limited through the use of jounce bumpers
in compression and shock absorbers in rebound.
REMOVAL
(1) Raise and support the vehicle.
(2) Support the rear axle with a hydraulic jack.
(3) Remove the ball joint nut from the top of the
upper suspension arm (Fig. 8).
(4) Separate ball joint from the arm with Remover
8278 (Fig. 9).
NOTE: It may be necessary to strike the upper con-
trol arm with a hammer to separate the ball joint
from the arm.
(5) Remove the ball joint mounting bolts (Fig.
10)from the differential housing.
(6) Remove the ball joint from the differential
housing.
Fig. 6 Isolator Spring Locator - Typical
1 - LOWER ISOLATOR
2 - SPRING LOCATOR
3 - COIL SPRING
Fig. 7 Rear Stabilizer Bar
1 - LINK
2 - RETAINER
3 - BUSHING
4 - STABILIZER BAR
WJREAR 2 - 21
SPRING (Continued)

INSTALLATION
(1) Install the ball joint on the differential hous-
ing.
(2) Install the ball joint mounting bolts and
tighten to 136 N´m (100 ft. lbs.).
(3) Raise the rear axle with a hydraulic jack to
align the upper arm with the ball joint.(4) Pull the arm down on the ball joint stud and
install anewnut. Tighten the nut to 142 N´m (105
ft. lbs.).
(5) Remove the supports and lower the vehicle.
UPPER CONTROL ARM
DESCRIPTION
The suspension arm uses vertical spool bushings to
isolate road noise. The suspension arm is bolted
through bushings to cage nuts in the body and a ball
joint plate to the top of the differential housing.
OPERATION
The upper suspension arm provides fore/aft and
lateral location of the rear axle. The suspension arm
travel is limited through the use of jounce bumpers
in compression and shock absorbers in rebound.
REMOVAL
(1) Raise and support the vehicle.
(2) Support the rear axle with a hydraulic jack.
(3) Remove the park brake cables and brake hose
from the arm (Fig. 11).
(4) Remove the ball joint nut from the top of the
upper suspension arm (Fig. 12).
(5) Separate ball joint from the arm with Remover
8278 (Fig. 13).
Fig. 8 Ball Joint Nut
1 - BALL JOINT NUT
2 - UPPER SUSPENSION ARM
Fig. 9 Separate Ball Joint
1 - REMOVER
2 - UPPER SUSPENSION ARM
3 - BALL JOINT STUD
Fig. 10 Ball Joint Mounting Bolts
1 - BALL JOINT
2 - MOUNTING BOLTS
2 - 22 REARWJ
UPPER BALL JOINT (Continued)

NOTE: It may be necessary to strike the upper con-
trol arm with a hammer to separate the ball joint
from the arm.
(6) Remove the upper suspension arm mounting
bolts and remove the arm (Fig. 14).
INSTALLATION
(1) Position the upper suspension arm in the
frame rail brackets.
(2) Install the mounting bolts and tighten to 100
N´m (74 ft. lbs.).
(3) Pull the arm down on the ball joint stud and
install anewnut. Tighten the nut to 142 N´m (105
ft. lbs.).(4) Install the park brake cables and brake hose to
the arm.
(5) Remove the supports and lower the vehicle.
Fig. 11 Park Brake Cables And Brake Hose
1 - UPPER SUSPENSION ARM
2 - REAR BRAKE HOSE
3 - PARK BRAKE CABLES
Fig. 12 Ball Joint Nut
1 - BALL JOINT NUT
2 - UPPER SUSPENSION ARM
Fig. 13 Separate Ball Joint
1 - REMOVER
2 - UPPER SUSPENSION ARM
3 - BALL JOINT STUD
Fig. 14 Upper Suspension Arm Mounting Bolt
1 - UPPER SUSPENSION ARM
2 - MOUNTING BOLT
WJREAR 2 - 23
UPPER CONTROL ARM (Continued)

VARI-LOKTDIFFERENTIAL
In a standard differential if one wheel spins, the
opposite wheel will generate only as much torque as
the spinning wheel.
A gerotor pump and clutch pack are used to pro-
vide the torque transfer capability. One axle shaft is
splined to the gerotor pump and one of the differen-
tial side gears, which provides the input to the pump.
As a wheel begins to lose traction, the speed differ-
ential is transmitted from one side of the differential
to the other through the side gears. The motion of
one side gear relative to the other turns the inner
rotor of the pump. Since the outer rotor of the pump
is grounded to the differential case, the inner and
outer rotors are now moving relative to each other
and therefore creates pressure in the pump. The tun-ing of the front and rear axle orifices and valves
inside the gerotor pump is unique and each system
includes a torque-limiting pressure relief valve to
protect the clutch pack, which also facilitates vehicle
control under extreme side-to-side traction varia-
tions. The resulting pressure is applied to the clutch
pack and the transfer of torque is completed.
Under conditions in which opposite wheels are on
surfaces with widely different friction characteristics,
Vari-loktdelivers far more torque to the wheel on
the higher traction surface than do conventional
Trac-loktsystems. Because conventional Trac-lokt
differentials are initially pre-loaded to assure torque
transfer, normal driving (where inner and outer
wheel speeds differ during cornering, etc.) produces
torque transfer during even slight side-to-side speed
variations. Since these devices rely on friction from
this preload to transfer torque, normal use tends to
cause wear that reduces the ability of the differential
to transfer torque over time. By design, the Vari-lokt
system is less subject to wear, remaining more con-
sistent over time in its ability to transfer torque. The
coupling assembly is serviced as a unit. From a ser-
vice standpoint the coupling also benefits from using
the same lubricant supply as the ring and pinion
gears.
DIAGNOSIS AND TESTING
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, 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 mate shaft can also cause a
snapping or a knocking noise.
Fig. 1 DIFFERENTIAL-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-ON TURNS
1 - PINION GEARS ROTATE ON PINION SHAFT
3 - 16 FRONT AXLE - 186FBIWJ
FRONT AXLE - 186FBI (Continued)

(7) Press metal retaining ring onto axle shaft with
Installer 7913 and a press (Fig. 30).
(8) Install axle in vehicle.
PINION SEAL
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies.
(3) Remove brake calipers and rotors.
(4) Mark propeller shaft and pinion yoke for
installation reference.
(5) Remove propeller shaft from the yoke.
(6) Rotate pinion gear a minimum of ten times and
verify pinion rotates smoothly.
(7) Record rotating torque of the pinion gear with
an inch pound dial-type torque wrench, for installa-
tion reference.
(8) Hold the pinion yoke with Spanner Wrench
6958 and remove the pinion nut and washer (Fig.
31).
(9) Remove pinion yoke with Remover C-452 and
Wrench C-3281 (Fig. 32).
(10) Remove pinion gear seal with Remover
7794-A and slide hammer (Fig. 33).
INSTALLATION
(1) Apply a light coating of gear lubricant on the
lip of pinion seal and install seal with an appropriate
installer (Fig. 34).
(2) Install yoke on pinion gear with Screw 8112,
Cup 8109 and Spanner Wrench 6958 (Fig. 35).
CAUTION: Do not exceed the minimum tightening
torque 271 N´m (200 ft. lbs.) when installing the pin-
ion yoke at this point. Damage to the collapsible
spacer or bearings may result.
(3) Install yoke washer and anewnut on the pin-
ion gear and tighten the nut until there is zero bear-
ing end-play.
Fig. 30 BEARING RETAINING RING
1 - PRESS
2 - AXLE
3 - AXLE BEARING
4 - INSTALLER
5 - METAL RETAINING RING
Fig. 31 PINION YOKE HOLDER
1 - PIPE
2 - PINION YOKE
3 - SPANNER WRENCH
4 - LOWER CONTROL ARM
Fig. 32 PINION YOKE
1 - FLANGE WRENCH
2 - YOKE
3 - YOKE PULLER
WJREAR AXLE - 198RBI 3 - 71
AXLE BEARINGS/SEALS (Continued)

(6) If the rotating torque is low, use Spanner
Wrench 6958 to hold the pinion yoke (Fig. 37), and
tighten the pinion nut in 6.8 N´m (5 ft. lbs.) incre-
ments until the proper rotating torque is achieved.
CAUTION: If maximum tightening torque is reached
prior to reaching required rotating torque, the col-
lapsible spacer may have been damaged. Replace
the collapsible spacer.
(7) Install the propeller shaft with reference marks
aligned.
(8) Add gear lubricant to the differential if neces-
sary.
(9) Install brake rotors and calipers.
(10) Install wheel and tire assemblies.
(11) Lower the vehicle.
COLLAPSIBLE SPACER
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies.
(3) Remove rear brake calipers and rotors.
(4) Mark propeller shaft and pinion yoke for
installation reference and remove propeller shaft.
(5) Rotate pinion gear a minimum of ten times and
verify pinion rotates smoothly.
(6) Record rotate torque of the pinion gear, with an
inch pound torque wrench.
(7) Hold pinion yoke with Spanner Wrench 6958
and remove pinion nut and washer (Fig. 38).
(8) Remove pinion yoke with Remover C-452 and
Wrench C-3281 (Fig. 39).(9) Remove pinion shaft seal with Remover 7794-A
and slide hammer (Fig. 40).
(10) Remove front pinion bearing using a pair of
pick tools to pull the bearing off the pinion gear
shaft.
NOTE: If the pinion bearing becomes bound on the
pinion shaft, lightly tap the end of the shaft with a
rawhide/rubber mallet.
(11) Remove the collapsible spacer.
INSTALLATION
(1) Install anewcollapsible spacer on pinion
shaft.
(2) Install pinion front bearing on the pinion shaft.
Fig. 37 PINION SHAFT NUT
1 - SPANNER WRENCH
2 - PIPE
3 - TORQUE WRENCH
Fig. 38 PINION YOKE HOLDER
1 - 1 in. PIPE
2 - PINION YOKE
3 - SPANNER WRENCH
4 - LOWER CONTROL ARM
Fig. 39 PINION YOKE PULLER
1 - WRENCH
2 - PINION YOKE
3 - PULLER
WJREAR AXLE - 198RBI 3 - 73
PINION SEAL (Continued)

INSTALLATION
NOTE: If differential side bearings or differential
case are replaced, differential side bearing shim
requirements may change. Refer to Adjustments
(Differential Bearing Preload and Gear Backlash) for
procedures.
(1) Install differential side bearings with Installer
C-3716-A and Handle C-4171 (Fig. 70).
(2) Install differential in axle housing.
(3) Remove support and lower vehicle.
PINION GEAR/RING GEAR
REMOVAL
NOTE: The ring and pinion gears are serviced as a
matched set. Never replace one gear without the
other gear.
(1) Raise and support vehicle.
(2) Mark pinion yoke and propeller shaft for
installation reference.
(3) Disconnect propeller shaft from pinion yoke
and tie shaft to underbody.
(4) Remove differential from the housing.
(5) Place differential case in a vise with soft metal
jaw.(6) Remove bolts holding ring gear to differential
case.
(7) Drive ring gear from differential case with a
rawhide hammer (Fig. 71).
(8) Hold the pinion yoke with Spanner Wrench
6958 and remove the pinion yoke nut and washer
(Fig. 72).
Fig. 70 Differential Side Bearing
1 - INSTALLER
2 - HANDLE
Fig. 71 RING GEAR
1 - DIFFERENTIAL CASE
2 - RING GEAR
3 - HAMMER
Fig. 72 PINION YOKE HOLDER
1 - 1 in. PIPE
2 - PINION YOKE
3 - HOLDER
4 - LOWER CONTROL ARM
3 - 84 REAR AXLE - 198RBIWJ
DIFFERENTIAL CASE BEARINGS (Continued)