2002 JEEP GRAND CHEROKEE Wheels

ing (Fig. 4) from the steering knuckle and off the
axle shaft.
INSTALLATION
(1) Install the hub bearing to the knuckle.
(2) Install the hub bearing to knuckle bolts and
tighten to 102 N´m (75 ft. lbs.).
(3) Install the hub washer and nut. Tighten the
hub nut to 237 N´m (175 ft. lbs.). Install the nut
retainer and a new cotter pin.
(4) Install the brake rotor, caliper anchor, caliper
and ABS wheel speed sensor,(Refer to 5 - BRAKES/
ELECTRICAL/FRONT WHEEL SPEED SENSOR -
INSTALLATION).
(5) Install the wheel and tire assembly (Refer to 22
- TIRES/WHEELS - STANDARD PROCEDURE).
(6) Remove the support and lower the vehicle.
KNUCKLE
DESCRIPTION
The knuckle is a single casting with legs machined
for the upper and lower ball joints. The knuckle also
has machined mounting locations for the front brake
calipers and hub bearing.
OPERATION
The steering knuckle pivot between the upper and
lower ball joint. Steering linkage attached to the
knuckle allows the vehicle to be steered.
REMOVAL - STEERING KNUCKLE
Ball stud service procedures below require removal
of the hub bearing and axle shaft. Removal andinstallation of upper and lower ball studs require the
use of Tool Kit 6289.
(1) Remove hub bearing and axle shaft.
(2) Disconnect the tie-rod or drag link from the
steering knuckle arm,(Refer to 19 - STEERING/
LINKAGE/TIE ROD END - REMOVAL) .
(3) Remove the cotter pins from the upper and
lower ball studs.
(4) Remove the upper and lower ball stud nuts.
(5) Strike the steering knuckle with a brass ham-
mer to loosen knuckle from the ball studs. Remove
knuckle from ball studs (Fig. 5).
INSTALLATION
(1) Position the steering knuckle on the ball studs.
(2) Install and tighten the bottom retaining nut to
109 N´m (80 ft. lbs.) torque. Install new cotter pin.
(3) Install and tighten the top retaining nut to 101
N´m (75 ft. lbs.) torque. Install new cotter pin.
(4) Install the hub bearing and axle shaft.
(5) Connect the tie-rod or drag link end to the
steering knuckle arm.,(Refer to 19 - STEERING/
LINKAGE/TIE ROD END - INSTALLATION) .
Fig. 4 Hub Bearing & Knuckle
1 - HUB BEARING
2 - KNUCKLE
Fig. 5 Steering Knuckle Removal/Installation
1 - AXLE YOKE
2 - UPPER BALL STUD
3 - LOWER BALL STUD
4 - STEERING KNUCKLE
2 - 10 FRONTWJ
HUB / BEARING (Continued)

DIFFERENTIAL & DRIVELINE
TABLE OF CONTENTS
page page
PROPELLER SHAFT......................1
FRONT TUBE AXLE......................14
FRONT AXLE - 186FBI....................15REAR AXLE - 198RBI.....................50
REAR AXLE - 226RBA....................90
PROPELLER SHAFT
TABLE OF CONTENTS
page page
PROPELLER SHAFT
DIAGNOSIS AND TESTING................1
STANDARD PROCEDURES................3
SPECIFICATIONS........................5
SPECIAL TOOLS........................5
PROPELLER SHAFT - FRONT
REMOVAL.............................6
INSTALLATION..........................6
PROPELLER SHAFT - FRONT 4.7L
REMOVAL.............................6INSTALLATION..........................7
PROPELLER SHAFT - REAR
REMOVAL.............................7
INSTALLATION..........................7
SINGLE CARDAN UNIVERSAL JOINTS
DISASSEMBLY..........................8
ASSEMBLY.............................9
DOUBLE CARDAN UNIVERSAL JOINTS
DISASSEMBLY..........................9
ASSEMBLY............................10
PROPELLER SHAFT
DIAGNOSIS AND TESTING
VIBRATION
Tires that are out-of-round, or wheels that are
unbalanced, will cause a low frequency vibration.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
Brake rotors that are unbalanced will cause a
harsh, low frequency vibration. (Refer to 5 - BRAKES
- DIAGNOSIS AND TESTING)Driveline vibration can also result from loose or
damaged engine mounts.
Propeller shaft vibration increases as the vehicle
speed is increased. A vibration that occurs within a
specific speed range is not usually caused by a pro-
peller shaft being unbalanced. Defective universal
joints, or an incorrect propeller shaft angle, are usu-
ally the cause of such a vibration.
WJDIFFERENTIAL & DRIVELINE 3 - 1

DRIVELINE VIBRATION
Drive Condition Possible Cause Correction
Propeller Shaft Noise 1) Undercoating or other foreign material
on shaft.1) Clean exterior of shaft and wash with
solvent.
2) Loose U-joint clamp screws. 2) Install new clamps and screws and
tighten to proper torque.
3) Loose or bent U-joint yoke or
excessive runout.3) Install new yoke.
4) Incorrect driveline angularity. 4) Measure and correct driveline angles.
5) Rear spring center bolt not in seat. 5) Loosen spring u-bolts and seat center
bolt.
6) Worn U-joint bearings. 6) Install new U-joint.
7) Propeller shaft damaged or out of
balance.7) Installl new propeller shaft.
8) Broken rear spring. 8) Install new rear spring.
9) Excessive runout or unbalanced
condition.9) Re-index propeller shaft, test, and
evaluate.
10) Excessive drive pinion gear shaft
runout.10) Re-index propeller shaft and evaluate.
11) Excessive axle yoke deflection. 11) Inspect and replace yoke if necessary.
12) Excessive transfer case runout. 12) Inspect and repair as necessary.
Universal Joint Noise 1) Loose U-joint clamp screws. 1) Install new clamps and screws and
tighten to proper torque.
2) Lack of lubrication. 2) Replace U-joints as necessary.
BALANCE
NOTE: Removing and re-indexing the propeller
shaft 180É relative to the yoke may eliminate some
vibrations.
If propeller shaft is suspected of being unbalanced,
it can be verified with the following procedure:
(1) Raise the vehicle.
(2) Clean all the foreign material from the propel-
ler shaft and the universal joints.
(3) Inspect the propeller shaft for missing balance
weights, broken welds, and bent areas.If the pro-
peller shaft is bent, it must be replaced.
(4) Inspect the universal joints to ensure that they
are not worn, are properly installed, and are cor-
rectly aligned with the shaft.
(5) Check the universal joint clamp screws torque.
(6) Remove the wheels and tires. Install the wheel
lug nuts to retain the brake drums or rotors.
(7) Mark and number the shaft six inches from the
yoke end at four positions 90É apart.
(8) Run and accelerate the vehicle until vibration
occurs. Note the intensity and speed the vibration
occurred. Stop the engine.(9) Install a screw clamp at position 1 (Fig. 1).
Fig. 1 CLAMP SCREW - POSITION 1
1 - CLAMP
2 - SCREWDRIVER
3 - 2 PROPELLER SHAFTWJ
PROPELLER SHAFT (Continued)

(10) Start the engine and re-check for vibration. If
there is little or no change in vibration, move the
clamp to one of the other three positions. Repeat the
vibration test.
(11) If there is no difference in vibration at the
other positions, the source of the vibration may not
be propeller shaft.
(12) If the vibration decreased, install a second
clamp (Fig. 2) and repeat the test.
(13) If the additional clamp causes an additional
vibration, separate the clamps (1/4 inch above and
below the mark). Repeat the vibration test (Fig. 3).
(14) Increase distance between the clamp screws
and repeat the test until the amount of vibration is
at the lowest level. Bend the slack end of the clamps
so the screws will not loosen.
(15) If the vibration remains unacceptable, apply
the same steps to the front end of the propeller shaft.
(16) Install the wheel and tires. Lower the vehicle.RUNOUT
(1) Remove dirt, rust, paint, and undercoating
from the propeller shaft surface where the dial indi-
cator will contact the shaft.
(2) The dial indicator must be installed perpendic-
ular to the shaft surface.
(3) Measure runout at the center and ends of the
shaft sufficiently far away from weld areas to ensure
that the effects of the weld process will not enter into
the measurements.
(4) Refer to Runout Specifications chart.
(5) If the propeller shaft runout is out of specifica-
tion, remove the propeller shaft, index the shaft 180É,
and re-install the propeller shaft. Measure shaft
runout again.
(6) If the propeller shaft runout is now within
specifications, mark the shaft and yokes for proper
orientation.
(7) If the propeller shaft runout is not within spec-
ifications, verify that the runout of the transmission/
transfer case and axle are within specifications.
Correct as necessary and re-measure propeller shaft
runout.
(8) Replace the propeller shaft if the runout still
exceeds the limits.
RUNOUT SPECIFICATIONS
Front of Shaft 0.020 in. (0.50 mm)
Center of Shaft 0.025 in. (0.63 mm)
Rear of Shaft 0.020 in. (0.50 mm)
note:
Measure front/rear runout approximately 3 inches (76
mm) from the weld seam at each end of the shaft
tube for tube lengths over 30 inches. For tube lengths
under 30 inches, the maximum allowed runout is
0.020 in. (0.50 mm) for the full length of the tube.
STANDARD PROCEDURES
This procedure applies to both the front propeller
shafts and the rear propeller shaft. To obtain the
front (output) angle on the C/V front propeller shaft,
the inclinometer is placed on the machined ring of
the pinion flange. To obtain the propeller shaft angle
measurement on the C/V front propeller shaft, the
inclinometer is placed on the propeller shaft tube.
PROPELLER SHAFT ANGLE
(1) Raise and support the vehicle at the axles as
level as possible. Allow the wheels and propeller
shaft to turn.
(2) Remove any external bearing snap rings from
universal joint if equipped, so the inclinometer base
will sits flat.
Fig. 2 TWO CLAMP SCREWS
Fig. 3 CLAMP SCREWS SEPARATED
1 - ó INCH
WJPROPELLER SHAFT 3 - 3
PROPELLER SHAFT (Continued)

FRONT TUBE AXLE
TABLE OF CONTENTS
page page
FRONT TUBE AXLE
REMOVAL.............................14INSTALLATION.........................14
FRONT TUBE AXLE
REMOVAL
(1) Raise and support the vehicle.
(2) Position a lifting device under the axle and
secure axle to lift.
(3) Remove the wheels and tires.
(4) Remove the brake rotors (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/ROTORS - REMOVAL)
and calipers.
(5) Disconnect wheel sensor wiring harness from
the vehicle wiring harness.
(6) Remove stabilizer bar links at the axle.
(7) Remove shock absorbers from axle brackets.
(8) Removet track bar.
(9) Remove tie rod and drag link from the steering
knuckle.
(10) Remove steering damper from the axle
bracket.
(11) Remove upper and lower suspension arms
from the axle brackets.
(12) Lower the lift enough to remove the axle. The
coil springs will drop with the axle.
(13) Remove the coil springs from the axle.
INSTALLATION
CAUTION: The weight of the vehicle must be sup-
ported by the springs before suspension arms and
track bar fasteners are tightened. If not at their nor-mal ride position, ride height and handling could be
affected.
(1) Install springs and retainer clips and tighten
retainer bolts to 21 N´m (16 ft. lbs.).
(2) Lift and position axle under the vehicle and
align it with the spring pads.
(3) Position upper and lower suspension arms in
the axle brackets and loosely install bolts and nuts.
(4) Install track bar to the axle bracket and loosely
install bolt.
(5) Install shock absorbers and tighten bolts to 23
N´m (17 ft. lbs.).
(6) Install stabilizer bar links to the axle brackets
and tighten nuts to 95 N´m (70 ft. lbs.).
(7) Install drag link and tie rod to the steering
knuckles.
(8) Install steering damper to the axle bracket and
tighten nut to 75 N´m (55 ft. lbs.).
(9) Install the brake rotors and calipers.
(10) Connect wheel speed sensor wiring harness, if
equipped.
(11) Install the wheel and tire assemblies.
(12) Remove lift from the axle and lower the vehi-
cle.
(13) Tighten upper suspension arm nuts to 75 N´m
(55 ft. lbs.). Tighten lower suspension arm nuts to
115 N´m (85 ft. lbs.).
(14) Tighten track bar bolt at the axle bracket to
100 N´m (74 ft. lbs.).
(15) Check the front wheel alignment.
3 - 14 FRONT TUBE AXLEWJ

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)

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)