2002 JEEP GRAND CHEROKEE rings

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)

SINGLE CARDAN UNIVERSAL
JOINTS
DISASSEMBLY
NOTE: Individual components of cardan universal
joints are not serviceable. If worn or leaking, they
must be replaced as an assembly.
(1) Remove the propeller shaft.
(2) Tap the outside of the bearing cap assembly
with a drift to loosen snap ring.
(3) Remove snap rings from both sides of yoke
(Fig. 12).
(4) Set the yoke in an arbor press or vise with a
socket whose inside diameter is large enough to
receive the bearing cap positioned beneath the yoke.
(5) Position the yoke with the grease fitting, if
equipped, pointing up.
(6) Place a socket with an outside diameter
smaller than the upper bearing cap on the upper
bearing cap and press the cap through the yoke to
release the lower bearing cap (Fig. 13).
(7) If the bearing cap will not pull out of the yoke
by hand after pressing, tap the yoke ear near the
bearing cap to dislodge the cap.
(8) To remove the opposite bearing cap, turn the
yoke over and straighten the cross in the open hole.
Then, carefully press the end of the cross until the
remaining bearing cap can be removed (Fig. 14).
CAUTION: If the cross or bearing cap are not
straight during installation, the bearing cap willscore the walls of the yoke bore and damage can
occur.
Fig. 12 REMOVE SNAP RING
1 - SNAP RING
Fig. 13 PRESS OUT BEARING
1 - PRESS
2 - SOCKET
Fig. 14 PRESS OUT REMAINING BEARING
1 - CROSS
2 - BEARING CAP
3 - 8 PROPELLER SHAFTWJ

ASSEMBLY
(1) Apply extreme pressure (EP) N.L.G.I. Grade 1
or 2 grease to inside of yoke bores.
(2) Position the cross in the yoke with its lube fit-
ting, if equipped, pointing up (Fig. 15).
(3) Place a bearing cap over the trunnion and
align the cap with the yoke bore (Fig. 16). Keep the
needle bearings upright in the bearing cap.
(4) Press the bearing cap into the yoke bore
enough to clear snap ring groove.
(5) Install a snap ring.
(6) Repeat Step 3 and Step 4 to install the oppo-
site bearing cap.
NOTE: If the joint is stiff or binding, strike the yoke
with a soft hammer to seat the needle bearings.
(7) Add grease to lube fitting, if equipped.
(8) Install the propeller shaft.
DOUBLE CARDAN UNIVERSAL
JOINTS
DISASSEMBLY
NOTE: Individual components of cardan universal
joints are not serviceable they must be replaced as
an assembly.(1) Remove the propeller shaft.
(2) Mark the propeller shaft yoke and link yoke for
assembly reference.
(3) Tap the outside of the bearing cap assembly
with drift to loosen snap rings.
(4) Remove all the bearing cap snap rings (Fig.
17).
Fig. 15 CROSS IN YOKE
1 - CROSS
2 - YOKE
Fig. 16 INSTALL BEARING ON TRUNNION
1 - BEARING CAP
2 - TRUNNION
Fig. 17 SNAP RINGS
WJPROPELLER SHAFT 3 - 9
SINGLE CARDAN UNIVERSAL JOINTS (Continued)

(3) Place a bearing cap over the trunnion and
align the cap with the yoke bore (Fig. 22). Keep nee-
dle bearings upright in the bearing cap.
(4) Press bearing cap into the yoke bore enough to
clear snap ring groove (Fig. 23).
(5) Install a snap ring.(6) Flip propeller shaft yoke and install other bear-
ing cap onto the opposite trunnion and install a snap
ring (Fig. 24).
(7) Fit the link yoke onto the remaining trunnions
and press both bearing caps into place and install
snap rings (Fig. 25).
Fig. 22 INSTALL BEARING CAP
Fig. 23 PRESS BEARING CAP
Fig. 24 PRESS BEARING CAP
Fig. 25 INSTALL LINK YOKE
WJPROPELLER SHAFT 3 - 11
DOUBLE CARDAN UNIVERSAL JOINTS (Continued)

(8) Install centering kit assembly inside the link
yoke (Fig. 26).
NOTE: Making sure the spring is properly posi-
tioned.
(9) Place two bearing caps on opposite trunnions of
the remaining cross. Fit the open trunnions into the
link yoke bores and the bearing caps into the center-
ing kit (Fig. 27).(10) Press the remaining two bearing caps into
place and install snap rings (Fig. 28).
(11) Tap the snap rings to seat them into the
grooves (Fig. 29).
Fig. 26 CENTERING KIT
Fig. 27 REMAINING CROSS
Fig. 28 PRESS BEARING CAP
Fig. 29 SEAT SNAP RINGS
3 - 12 PROPELLER SHAFTWJ
DOUBLE CARDAN UNIVERSAL JOINTS (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

FRONT AXLE - 186FBI
TABLE OF CONTENTS
page page
FRONT AXLE - 186FBI
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING................16
REMOVAL.............................20
INSTALLATION.........................21
ADJUSTMENTS........................21
SPECIFICATIONS.......................30
SPECIAL TOOLS.......................31
AXLE SHAFTS
REMOVAL.............................34
INSTALLATION.........................34
AXLE SHAFT SEALS
REMOVAL.............................35
INSTALLATION.........................35
AXLE - C/V JOINT
REMOVAL.............................35
INSTALLATION.........................35
AXLE - U-JOINT
REMOVAL.............................36INSTALLATION.........................37
PINION SEAL
REMOVAL.............................37
INSTALLATION.........................37
COLLAPSIBLE SPACER
REMOVAL.............................39
INSTALLATION.........................39
DIFFERENTIAL
REMOVAL.............................40
DISASSEMBLY.........................42
ASSEMBLY............................42
INSTALLATION.........................43
DIFFERENTIAL CASE BEARINGS
REMOVAL.............................44
INSTALLATION.........................44
PINION GEAR/RING GEAR
REMOVAL.............................45
INSTALLATION.........................46
FRONT AXLE - 186FBI
DESCRIPTION
The Front Beam-design Iron (FBI) axle consists of
a cast iron differential housing with axle shaft tubes
extending from either side. The tubes are pressed
into the differential housing and welded. The axles
are semi-floating axle shafts, meaning the loads are
supported by the hub bearings. The axle shafts are
retained by nuts at the hub bearings.
The differential case is a one-piece design. Differ-
ential bearing preload and ring gear backlash is
adjusted by the use of shims located between the dif-
ferential bearing cups and housing. Pinion bearing
preload is set and maintained by the use of a collaps-
ible spacer. A differential cover provides a means for
inspection and servicing.
An optional Vari-Loktdifferential has a one-piece
differential case which contains the gerotor pump
assembly and the clutch mechinism. This unit is ser-
viced as an assembly.
OPERATION
The axle receives power from the transfer case
through the front propeller shaft. The front propeller
shaft is connected to the pinion gear which rotatesthe 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 pinion
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 pin-
ion 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.
WJFRONT AXLE - 186FBI 3 - 15