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REAR SUSPENSION AND AXLES 3 - 1
REAR SUSPENSION AND AXLES
CONTENTS
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AXLE NOISE/VIBRATION DIAGNOSIS .........
GENERAL INFORMATION ..................
MODEL 35 AXLE ........................
REAR SUSPENSION ......................
TORQUE SPECIFICATIONS ................
TRAC-LOK DIFFERENTIAL ................
GENERAL INFORMATION
REAR SUSPENSION
The Grand Cherokee rear suspension is link/coil
design comprised of (Fig. 1);
²
Drive axle
The upper suspension arm uses cam bolts at the axle
to allow for pinion angle adjustment. The cams are
available as a service kit and are not installed at the
factory. The suspension arm travel (jounce or re-
bound) is limited through the use rubber bumpers.
All suspension components that use rubber bush-
ings should be tightened with the vehicle at the nor-
mal height. If the springs are not at normal ride
position, vehicle ride comfort could be affected. Rub-
ber bushings must never be lubricated.
The vehicles use coil springs mounted up in the
fender shield that is part of the unitized body bracket.
There is a rubber doughnut isolator between the top
of the spring and bracket to isolate road noise. The
bottom of the spring seats on the axle pad and is
retained with a clip.
Ride control is accomplished through the use of
dual-action shock absorbers. The shocks dampen
jounce and rebound as the vehicle travels over vari-
ous road conditions. The top of the shock absorbers
are bolted to the frame brackets. The bottom of the
shocks are bolted to the axle brackets.
The stabilizer bar is used to minimize vehicle rear
sway during turns. The spring steel bar helps to
equalize the vehicle body in relationship to the sus-
pension. The bar extends across the underside of the
chassis and connects to the frame rails. The links are
connected to the axle brackets. All mounting points of
the stabilizer bar are isolated by rubber bushings.
The track bar is used to minimize rear axle side-to-
side movement. The track bar is attached to the
frame rail bracket with a ball stud and isolated with
a bushing at the axle bracket.
²
Coil springs
²
Upper and lower suspension arms
²
Dual-action shock absorbers
²
Track bar
²
Stabilizer bar
Jounce bumpers (used to limit the travel of the
suspension)
Fig. 1 Rear Suspension
REAR AXLE
The integral housing, hypoid design has the pinion
set below the ring gear.
The axles are equipped with A.B.S. brake systems.
The A.B.S. tone rings are pressed onto the axle shaft
The upper and lower suspension arms use bushings
to isolate road noise. The suspension arms are bolted
to the frame and axle through the rubber bushings.
²
 3 - 2 REAR SUSPENSION AND AXLES
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near the hub flange. For additional information on
the A.B.S. system refer to Group 5, Brakes.
The Model 35 axle has the assembly part number
and gear ratio listed on a tag. The tag is attached to
the housing cover (Fig. 2). Build date identification
codes are stamped on the axle shaft tube cover side.
The Model 35 axle is available with Trac-lok (lim-
ited slip) differential as an option.
Fig. 3 Differential Operation—Straight-Ahead
Driving
Fig. 2 Model 35 Differential Cover
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. 3).
When turning corners, the outside wheel must
travel a greater distance than the inside wheel in
order to complete a turn. This difference must be
compensated for in order to prevent the wheels from
scuffing and skidding through the turn. To accomplish
this, the differential becomes effective allowing the
axle shafts to turn at unequal speeds (Fig. 4). 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.
STANDARD DIFFERENTIAL OPERATION
The differential gear system divides the torque be-
tween the axle shafts. It allows the axle shafts to
rotate at different speeds when turning corners.
Each differential side gear is splined to an axle
shaft. The pinion gears are mounted on a pinion mate
shaft and are free to rotate on the shaft. The pinion
gear is fitted in a bore in the differential case and is
positioned at a right angle to the axle shafts.
In operation, power flow occurs as follows:
²
Pinion gear rotates the ring gear
Ring gear (bolted to the differential case) rotates
the case
²
Differential pinion gears (mounted on the pinion
mate shaft in the case) rotate the side gears
²
Side gears (splined to the axle shafts) rotate the
shafts
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
Fig. 4 Differential Operation—On Turns
²
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REAR SUSPENSION AND AXLES 3 - 3
REAR SUSPENSION
INDEX
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Coil Spring .............................
Lower Suspension Arm ....................
Service Information .......................
Shock Absorber ..........................
Spring and Shock Diagnosis ..................
Stabilizer Bar ............................
Track Bar ..............................
Upper Suspension Arm ....................
SERVICE INFORMATION
INSTALLATION
(1) Install the track bar to the axle bracket and
install the bolt (Fig. 1).
(2) It may be necessary to pry the axle assembly
over to install the track bar. Install the track bar to
the frame rail bracket. Loosely install the bolt and
flag nut (Fig. 1).
(3) Remove the supports and lower the vehicle.
(4) Tighten the bolt at the axle shaft tube bracket
to 100 N
CAUTION: All suspension components that use rub-
ber bushings should be tightened with the vehicle at
the normal height. Have the springs supporting the
weight of vehicle when fasteners are torqued. If the
springs are not at their normal ride position, vehicle
ride comfort could be affected. Rubber bushings
must never be lubricated.
m (74 ft. lbs.) torque.
(5) Tighten the nut at the frame rail to 100 N
TRACK BAR
m
(74 ft. lbs.) torque.
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the bolt and nut from the frame rail
bracket (Fig. 1).
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle. Remove one
wheel and tire.
(2) Disconnect the stabilizer bar links from the axle
brackets (Fig. 2).
(3) Lower the exhaust by disconnecting the muffler
and tail pipe hangers.
(4) Disconnect the stabilizer bar from the links.
(5) Disconnect the stabilizer bar clamps from the
frame rails. Remove the stabilizer bar.
Fig. 1 Rear Track Bar
(3) Remove the bolt from the axle tube bracket
(Fig. 1). Remove the track bar.
Fig. 2 Rear Stabilizer Bar
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 3 - 4 REAR SUSPENSION AND AXLES
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INSTALLATION
(1) Position the stabilizer bar on the frame rail and
install the clamps and bolts. Ensure the bar is cen-
tered with equal spacing on both sides. Tighten the
bolts to 54 N
LOWER SUSPENSION ARM
m (40 ft. lbs.).
(2) Install the links and grommets onto the stabi-
lizer bar and axle brackets (Fig. 2). Install the nuts
and tighten to 36 N
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the lower suspension arm nut and bolt
at the axle bracket (Fig. 3).
(3) Remove the nut and bolt (Fig. 3) at the frame
rail and remove the lower suspension arm.
m (27 ft. lbs.) torque.
(3) Connect the muffler and tail pipe to their hang-
ers.
(4) Install the wheel and tire.
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INSTALLATION
(1) Position the lower suspension arm at the axle
bracket and frame rail bracket (Fig. 3).
(2) Install the bolts and finger tighten the nuts
(Fig. 3).
(3) Remove the supports and lower the vehicle.
(4) Tighten the nut at the axle bracket to 177 N
UPPER SUSPENSION ARM
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the upper suspension arm nut and bolt
at the axle bracket (Fig. 3). Remove the ABS wire
bracket from the arm.
(3) Remove the nut and bolt (Fig. 3) at the frame
rail and remove the upper suspension arm.
m
(130 ft. lbs.) torque.
(5) Tighten the bolt at the frame rail to 177 N
m
(130 ft. lbs.) torque.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber can be
produced if movement between the rubber bushings
and the metal occurs. This noise can usually be
stopped by tightening the attaching nuts. If the
squeak noise persists, inspect for damaged and worn
bushings, and attaching components. Repair as neces-
sary if any of these conditions exist.
The shock absorbers are not refillable or adjustable.
If a malfunction occurs, the shock absorber must be
replaced. To test a shock absorber, hold it in an up-
right position and force the piston into and out of the
cylinder four or five times. The action throughout
each stroke should be smooth and even.
SHOCK ABSORBER
REMOVAL
(1) Remove the upper nut and retainer from the
frame rail stud (Fig. 4).
(2) Remove the lower nuts and bolts from the axle
bracket. Remove the shock absorber.
Fig. 3 Upper and Lower Suspension Arms
INSTALLATION
(1) Install the shock absorber on the upper frame
rail stud. Install the shock absorber on the axle
bracket (Fig. 4).
(2) Install the retainer and nut on the stud.
Tighten the upper nut to 70 N
INSTALLATION
(1) Position the upper suspension arm at the axle
and frame rail (Fig. 3).
(2) Install the bolts and finger tighten the nuts
(Fig. 3). Install the ABS wire bracket onto the arm.
(3) Remove the supports and lower the vehicle.
(4) Tighten the nut at the axle bracket to 75 N
m (52 ft. lbs.) torque.
(3) Tighten the lower nut to 92 N
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m (68 ft. lbs.)
torque.
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m
COIL SPRING
(55 ft. lbs.) torque.
(5) Tighten the nut at the frame rail to 75 N
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m (55
REMOVAL
(1) Raise and support the vehicle. Position a hy-
draulic jack under the axle to support it.
(2) Disconnect the stabilizer bar link and shock
absorber from the axle bracket.
ft. lbs.) torque.
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REAR SUSPENSION AND AXLES 3 - 5
(3) Disconnect the track bar from the frame rail
bracket.
(4) Lower the axle until the spring is free from the
upper mount seat. Remove the coil spring clip screw
(Fig. 4) and remove the spring.
m (16 ft. lbs.) torque.
(2) Raise the axle into position until the spring
seats in the upper mount.
(3) Connect the stabilizer bar links and shock ab-
sorbers to the axle bracket. Connect the track bar to
the frame rail bracket.
(4) Remove the supports and lower the vehicle.
Fig. 4 Rear Coil Spring & Shock Absorber
INSTALLATION
(1) Position the coil spring on the axle pad. Install
the spring clip and screw (Fig. 4). Tighten the screw
to 22 N
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