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²Wheel bearings
²Engine
²Transmission
²Exhaust
²Propeller shaft (vibration)
²Vehicle body (drumming)
Driveline module noises are normally divided into
two categories: gear noise or bearing noise. A thor-
ough and careful inspection should be completed to
determine the actual source of the noise before
replacing the driveline module.
The rubber mounting bushings help to dampen-out
driveline module noise when properly installed.
Inspect to confirm that no metal contact exists
between the driveline module case and the body. The
complete isolation of noise to one area requires
expertise and experience. Identifying certain types of
vehicle noise baffles even the most capable techni-
cians. Often such practices as:
²Increase tire inflation pressure to eliminate tire
noise.
²Listen for noise at varying speeds with different
driveline load conditions
²Swerving the vehicle from left to right to detect
wheel bearing noise.
All driveline module assemblies produce noise to a
certain extent. Slight carrier noise that is noticeable
only at certain speeds or isolated situations should be
considered normal. Carrier noise tends to peak at a
variety of vehicle speeds. Noise isNOT ALWAYSan
indication of a problem within the carrier.
TIRE NOISE
Tire noise is often mistaken for driveline module
noise. Tires that are unbalanced, worn unevenly or
are worn in a saw-tooth manner are usually noisy.
They often produce a noise that appears to originate
in the driveline module.
Tire noise changes with different road surfaces, but
driveline module noise does not. Inflate all four tires
with approximately 20 psi (138 kPa) more than the
recommended inflation pressure (for test purposes
only). This will alter noise caused by tires, but will
not affect noise caused by the differential. Rear axle
noise usually ceases when coasting at speeds less
than 30 mph (48 km/h); however, tire noise contin-
ues, but at a lower frequency, as the speed is
reduced.
After test has been completed lower tire pressure
back to recommended pressure.
GEAR NOISE (DRIVE PINION AND RING GEAR)
Abnormal gear noise is rare and is usually caused
by scoring on the ring gear and drive pinion. Scoring
is the result of insufficient or incorrect lubricant in
the carrier housing.Abnormal gear noise can be easily recognized. It
produces a cycling tone that will be very pronounced
within a given speed range. The noise can occur dur-
ing one or more of the following drive conditions:
²Drive
²Road load
²Float
²Coast
Abnormal gear noise usually tends to peak within
a narrow vehicle speed range or ranges. It is usually
more pronounced between 30 to 40 mph (48 to 64
km/h) and 50 to 60 mph (80 to 96 km/h). When objec-
tionable gear noise occurs, note the driving condi-
tions and the speed range.
BEARING NOISE (DRIVE PINION AND
DIFFERENTIAL)
Defective bearings produce a rough growl that is
constant in pitch and varies with the speed of vehi-
cle. Being aware of this will enable a technician to
separate bearing noise from gear noise.
Drive pinion bearing noise that results from defec-
tive or damaged bearings can usually be identified by
its constant, rough sound. Drive pinion front bearing
is usually more pronounced during a coast condition.
Drive pinion rear bearing noise is more pronounced
during a drive condition. The drive pinion bearings
are rotating at a higher rate of speed than either the
differential side bearings or the axle shaft bearing.
Differential side bearing noise will usually produce
a constant, rough sound. The sound is much lower in
frequency than the noise caused by drive pinion bear-
ings.
Bearing noise can best be detected by road testing
the vehicle on a smooth road (black top). However, it
is easy to mistake tire noise for bearing noise. If a
doubt exists, the tire treads should be examined for
irregularities that often causes a noise that resem-
bles bearing noise.
ENGINE AND TRANSMISSION NOISE
Sometimes noise that appears to be in the driv-
eline module assembly is actually caused by the
engine or the transmission. To identify the true
source of the noise, note the approximate vehicle
speed and/or RPM when the noise is most noticeable.
Stop the vehicle next to a flat brick or cement wall
(this will help reflect the sound). Place the transaxle
inNEUTRAL. Accelerate the engine slowly up
through the engine speed that matches the vehicle
speed noted when the noise occurred. If the same
noise is produced, it usually indicates that the noise
is being caused by the engine or transaxle.
3 - 26 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)
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Page 106 of 2399

DIAGNOSIS AND TESTING - REAR DRIVELINE
MODULE OPERATION
Driveline module operation requires relatively
straight-forward diagnosis. Refer to the following
chart:
DRIVELINE MODULE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Rear wheels not
overrunning1) Bi-directional overrunning clutch
failure1) Replace overrunning clutch
components as required
No AWD in forward or
reverse directions, propeller
shaft turning1) Bi-directional overrunning clutch
failure1) Replace overrunning clutch
components as required
2) Viscous coupling failure 2) Replace viscous coupling
3) Rear differential failure 3) Replace the rear differential
assembly
No AWD in forward or
reverse directions, propeller
shaft not turning1) Power transfer unit failure. 1) Replace power transfer unit
components as necessary
Vibration at all speeds,
continuous torque transfer1) Mis-matched tires, worn tires on
front axle.1) Replace worn or incorrect
(mis-matched) tires with same
make and size
REMOVAL
(1) Raise vehicle on hoist.
(2) Drain fluid from overrunning clutch housing
and/or differential assembly if necessary.
(3) Remove propeller shaft. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/PROPELLER SHAFT -
REMOVAL)
(4) Disconnect left and right rear halfshafts from
output flanges (Fig. 2).(5) Remove torque arm mount to body bolts.
(6) Position transmission jack to driveline module
assembly and secure assembly to jack.
(7) Remove two driveline module-to-body bolts
(Fig. 3).
(8) Lower driveline module from vehicle and
remove from jack.
Fig. 2 Half Shaft Mounting Bolts
1 - SHAFT
2 - FLANGE
Fig. 3 Rear Drive Line Module Assembly Mounting
Bolts
1 - DRIVELINE MODULE RETAINING BOLT (2)
2 - RUBBER ISOLATOR
3 - WASHER
RSREAR DRIVELINE MODULE3-27
REAR DRIVELINE MODULE (Continued)
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Page 107 of 2399
DISASSEMBLY
WARNING: Differential is only to be serviced as an
assembly, and no disassembly is required.
(1) Remove six torque arm-to-differential case
bolts and remove torque arm assembly (Fig. 4).
(2) Remove input flange nut and washer using
Tool 6958 and a breaker bar (Fig. 5).(3) Remove input flange (Fig. 6).
(4) Remove input flange seal from overrunning
clutch housing using suitable screwdriver (Fig. 7).
Fig. 4 Torque Arm Fasteners
1 - TORQUE ARM ASSEMBLY
2 - BOLT (SIX)
Fig. 5 Input Flange Nut
1 - INPUT FLANGE
2 - TOOL 6958
Fig. 6 Input Flange
1 - INPUT FLANGE/SHIELD
Fig. 7 Input Flange Seal Removal
1 - INPUT FLANGE SEAL
2 - SCREWDRIVER
3 - 28 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)
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Page 108 of 2399
(5) Remove four overrunning clutch housing-to-dif-
ferential assembly bolts (Fig. 8) and remove housing.
(6) Remove front bearing snap ring (Fig. 14).
(7) Remove front bearing (Fig. 14).
(8) Remove o-ring and washer from overrunning
clutch assembly (Fig. 14).
(9) Remove overrunning clutch assembly from vis-
cous coupler (Fig. 9).(10) Remove viscous coupler from differential pin-
ion shaft (Fig. 10).
(11) Remove shim (select) from differential pinion
gear (Fig. 11).
Fig. 8 Overrunning Clutch Housing Bolts
1 - OVERRUNNING CLUTCH HOUSING
2 - BOLT (FOUR)
Fig. 9 Overrunning Clutch
1 - OVERRUNNING CLUTCH
2 - VISCOUS COUPLER
Fig. 10 Viscous Coupler
1 - VISCOUS COUPLER
2 - DIFFERENTIAL PINION
Fig. 11 Shim (Select)
1 - SHIM (SELECT)
2 - DIFFERENTIAL PINION
RSREAR DRIVELINE MODULE3-29
REAR DRIVELINE MODULE (Continued)
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Page 109 of 2399
(12) Remove overrunning clutch housing large
o-ring from differential assembly (Fig. 14).
(13) Remove output flanges using suitable screw-
drivers and wood blocks to protect casting (Fig. 12).(14) Remove output flange seals (Fig. 13).
ASSEMBLY
(1) Install output flange seals using tools C4171
and 8493 (Fig. 15).
(2) Install large overrunning clutch housing o-ring
to differential assembly (Fig. 14).
(3) Install shim to differential pinion shaft (Fig.
16).
Fig. 12 Output Flange Removal
1 - WOOD BLOCK
2 - PRYBAR
3 - OUTPUT SHAFT
4 - PRYBAR
5 - WOOD BLOCK
6 - DIFFERENTIAL CASE
Fig. 13 Output Flange Seal Removal
1 - OUTPUT FLANGE SEAL
2 - SCREWDRIVER
3 - 30 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)
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Page 110 of 2399
Fig. 14 Drive Line Module
1 - NUT, INPUT FLANGE 6 - BEARING, FRONT 11 - VISCOUS COUPLER
2 - WASHER, INPUT FLANGE NUT 7 - SNAP RING, BEARING RETAINER 12 - O-RING, OVERRUNNING CLUTCH
HOUSING
3 - INPUT FLANGE/SHIELD 8 - O-RING 13 - SHIM (SELECT)
4 - SEAL, INPUT FLANGE 9 - WASHER 14 - DIFFERENTIAL ASSEMBLY
5 - OVERRUNNING CLUTCH HOUSING
BOLT10 - BI-DIRECTIONAL OVERRUNNING
CLUTCH
Fig. 16 Shim (Select)
1 - SHIM (SELECT)
2 - DIFFERENTIAL PINION
Fig. 15 Output Flange Seal Installation
1 - DRIVER HANDLE C4171
2 - INSTALLER 8493
RSREAR DRIVELINE MODULE3-31
REAR DRIVELINE MODULE (Continued)
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Page 111 of 2399
(4) Install viscous coupler to differential pinion
shaft (Fig. 17).
(5) Install overrunning clutch assembly to viscous
coupler (Fig. 18).(6) Install washer to overrunning clutch (Fig. 14).
(7) Install o-ring to overrunning clutch (Fig. 14).
(8) Align overrunning clutch ground tab to 12
o'clock position (Fig. 19).
(9) Install overrunning clutch housing into posi-
tion, making sure ground tab engages with notch in
housing (Fig. 20).
Fig. 17 Viscous Coupler
1 - VISCOUS COUPLER
2 - DIFFERENTIAL PINION
Fig. 18 Overrunning Clutch
1 - OVERRUNNING CLUTCH
2 - VISCOUS COUPLER
Fig. 19 Grounding Tab at 12 O'clock
1 - OVERRUNNING CLUTCH
2 - GROUND TAB
Fig. 20 Overrunning Clutch Housing
1 - OVERRUNNING CLUTCH HOUSING
2 - NOTCH
3 - 32 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)
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Page 112 of 2399
(10) Install and torque overrunning clutch hous-
ing-to-differential assembly bolts (Fig. 21) to 60 N´m
(44 ft. lbs.).
(11) Install input flange seal using tool 8802 (Fig.
22).(12) Install flange/shield assembly (Fig. 23).
(13) Install input flange washer and nut. Using
tool 6958 (Fig. 24), torque nut to 135 N´m (100 ft.
lbs.).
Fig. 21 Overrunning Clutch Housing Bolts
1 - OVERRUNNING CLUTCH HOUSING
2 - BOLT (FOUR)
Fig. 22 Input Flange Seal Installation
1 - TOOL 8802
2 - HAMMER
Fig. 23 Input Flange/Shield
1 - INPUT FLANGE/SHIELD
Fig. 24 Input Flange Nut
1 - INPUT FLANGE
2 - TOOL 6958
RSREAR DRIVELINE MODULE3-33
REAR DRIVELINE MODULE (Continued)
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