(4) Install the half shaft washer and hub nut.
Torque the hub nut to 244 N´m (180 ft.lbs.).
(5) Install the wave washer, nut lock, and a new
cotter pin (Fig. 6). Be sure to wrap the cotter pin
prongs tightly around the hub nut lock.(6) Install rear wheel. Torque the lug nuts to 135
N´m (100 ft.lbs.).
SPECIFICATIONS - HALF SHAFT - FRONT
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Nut, Hub 244 180 -
Nuts, Rear Wheel Lug 135 100 -
Bolt, Half Shaft to Output Flange 61 45 -
Fig. 5 Inner Half Shaft Bolts
1 - SHAFT
2 - FLANGE
Fig. 6 Cotter Pin, Nut Lock, And Wave Washer
1 - HUB NUT
2 - NUT LOCK
3 - COTTER PIN
4 - SPRING WASHER
3 - 16 HALF SHAFT - REARRS
HALF SHAFT - REAR (Continued)
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CRIMP TYPE BOOT CLAMP
If seal boot uses crimp type boot clamp, use the fol-
lowing procedure to install the retaining clamp.
(1) Place crimping tool C-4975-A over bridge of
clamp (Fig. 21).
(2) Tighten nut on crimping tool C-4975-A until
jaws on tool are closed completely together, face to
face (Fig. 22).
LATCHING TYPE BOOT CLAMP
If seal boot uses low profile latching type boot
clamp, use the following procedure to install the
retaining clamp.
(1) Place prongs of clamp locking tool in the holes
of the clamp (Fig. 23).
(2) Squeeze tool together until top band of clamp is
latched behind the two tabs on lower band of clamp
(Fig. 24).
(16) Install the half shaft into the vehicle. (Refer
to 3 - DIFFERENTIAL & DRIVELINE/HALF SHAFT
- INSTALLATION)
Fig. 21 Crimping Tool Installed on Sealing Boot
Clamp - Typical
1 - CLAMP
2 - TRIPOD JOINT HOUSING
3 - SPECIAL TOOL C-4975-A
4 - SEALING BOOT
Fig. 22 Sealing Boot Retaining Clamp Installed -
Typical
1 - CLAMP
2 - TRIPOD HOUSING
3 - SPECIAL TOOL C-4975-A
4 - JAWS OF SPECIAL TOOL C-4975-A MUST BE CLOSED
COMPLETELY TOGETHER HERE
5 - SEALING BOOT
Fig. 23 Clamping Tool Installed on Sealing Boot
Clamp
1 - CLAMP
2 - TOOL YA3050, OR EQUIVALENT
3 - SEALING BOOT
Fig. 24 Sealing Boot Clamp Correctly Installed
1 - INNER TRIPOD JOINT HOUSING
2 - TOP BAND OF CLAMP MUST BE RETAINED BY TABS AS
SHOWN HERE TO CORRECTLY LATCH BOOT CLAMP
3 - SEALING BOOT
RSHALF SHAFT - REAR3-21
CV BOOT - INNER/OUTER (Continued)
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adjustment, maintenance or fluid checks required
during the life of the unit.
The overrunning clutch allows the rear wheels to
overrun the front wheels during a rapid front wheel
lock braking maneuver. The overrunning action pre-
vents any feed-back of front wheel braking torque to
the rear wheels. It also allows the braking system to
control the braking behavior as a two wheel drive
(2WD) vehicle.
The overrunning clutch housing has a separate oil
sump and is filled independently from the differen-
tial. The fill plug is located on the side of the over-
running clutch case. When filling the overrunning
clutch with lubricant use MopartATF+4 (Automatic
Transmission FluidÐType 9602) or equivalent.
The differential assembly contains a conventional
open differential with hypoid ring gear and pinion
gear set. The hypoid gears are lubricated by SAE
80W-90 gear lubricant.DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - REAR DRIVELINE
MODULE NOISE
Different sources can be the cause of noise that the
rear driveline module assembly is suspected of mak-
ing. Refer to the following causes for noise diagnosis.
DRIVELINE MODULE ASSEMBLY NOISE
The most important part of driveline module ser-
vice is properly identifying the cause of failures and
noise complaints. The cause of most driveline module
failures is relatively easy to identify. The cause of
driveline module noise is more difficult to identify.
If vehicle noise becomes intolerable, an effort
should be made to isolate the noise. Many noises that
are reported as coming from the driveline module
may actually originate at other sources. For example:
²Tires
²Road surfaces
Fig. 1 AWD Driveline Module Assembly
1 - TORQUE ARM 8 - WASHER 15 - PLUG-OVERRUNNING CLUTCH HOUSING DRAIN
2 - INPUT FLANGE 9 - BI-DIRECTIONAL OVERRUNNING CLUTCH (BOC) 16 - SNAP RING
3 - FLANGE NUT 10 - VISCOUS COUPLER 17 - BEARING
4 - WASHER 11 - SHIM (SELECT) 18 - OVERRUNING CLUTCH HOUSING
5 - SHIELD 12 - O-RING 19 - SEAL-INPUT FLANGE
6 - VENT 13 - DIFFERENTIAL ASSEMBLY
7 - O-RING 14 - PLUG-DIFFERENTIAL FILL
RSREAR DRIVELINE MODULE3-25
REAR DRIVELINE MODULE (Continued)
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(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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(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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BI-DIRECTIONAL
OVERRUNNING CLUTCH
DESCRIPTION
The bi-directional overrunning clutch (BOC) (Fig.
28) works as a mechanical disconnect between the
front and rear axles, preventing torque from being
transferred from the rear axle to the front. The BOC
is a simply an overrunning clutch which works in
both clockwise and counter-clockwise rotations. This
means that when the output (the rear axle) is rotat-
ing faster in one direction than the input (front axle),
there is no torque transmission. But when the input
speed is equal to the output speed, the unit becomes
locked. The BOC provides significant benefits regard-
ing braking stability, handling, and driveline durabil-
ity. Disconnecting the front and the rear driveline
during braking helps to maintain the braking stabil-
ity of an AWD vehicle. In an ABS/braking event, the
locking of the rear wheels must be avoided for stabil-
ity reasons. Therefore brake systems are designed to
lock the front wheels first. Any torque transfer from
the rear axle to the front axle disturbs the ABS/brak-
ing system and causes potential instabilities on aslippery surface. The BOC de-couples the rear driv-
eline as soon the rear wheels begin to spin faster
than the front wheels (front wheels locked) in order
to provide increased braking stability. Furthermore
the BOC also reduces the likelihood of throttle off
over-steer during cornering. In a throttle off maneu-
ver, the BOC once again de-couples the rear driveline
forcing all the engine brake torque to the front
wheels. This eliminates the chance of lateral slip on
the rear axle and increases it on the front. The vehi-
cle will therefore tend to understeer, a situation
which is considered easier to manage in most circum-
stances. During this maneuver, and during the ABS
braking event, the BOC does not transmit torque
through to the rear wheels. The rear driveline mod-
ule, with the BOC, will perform the same as a front
wheel drive vehicle during these events. The gear
ratio offset between the front and rear differentials
force the BOC into the overrunning mode most of the
time. This allows BOC to significantly reduce the
rolling resistance of the vehicle, which improves fuel
consumption, allows the downsizing of the driveline
components, and prevents the PTU and propshaft
joints from overheating.
3 - 36 REAR DRIVELINE MODULERS
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Fig. 28 Bi-directional Overrunning Clutch and Viscous Coupler
1 - POWERFLOW - BOC OVERUNNING 6 - VISCOUS COUPLER
2 - POWERFLOW - BOC LOCKED 7 - BOC ROLLER CAGE
3 - BOC GROUND TAB 8 - BOC INPUT SHAFT
4 - FRICTION BRAKE SHOES 9 - INPUT FLANGE
5 - BOC ROLLERS
RSREAR DRIVELINE MODULE3-37
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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OPERATION
In order to achieve all-wheel drive operation in
reverse, the overrunning clutch locking functional direc-
tion must be reversible. The bi-directional overrunning
clutch (BOC) changes the operational mode direction
depending on the propeller shaft direction. The propel-
ler shaft rotates in the clockwise (when viewed from the
front) direction when the vehicle is moving forward,
which indexes the BOC to the forward overrunning
position. When the vehicle is in reverse, the propeller
shaft will rotate counter-clockwise and index the BOC
to the reverse overrunning position.
The BOC acts as a mechanical stator. It is active
(transmitting torque), or it is not active and in over-
running mode (not transmitting torque). This ªall or
nothingº approach to torque transfer would cause a
sudden application of all available power to the rear
wheels, which is not desirable. Therefore it is run in
series with a viscous coupler to smooth, dampen, and
limit the transmission of torque to the rear axle and
to prevent a step style torque input to the rear axle.
STEADY STATE, LOW TO MODERATE SPEED, NO
FRONT WHEEL SLIP, FORWARD DIRECTION
During normal driving conditions, (no wheel slip), the
inner shaft (front axle) and outer race (viscous coupler)
are running at different speeds due to the different gear
ratios between the front and rear differentials. In this
condition, the outer race is always spinning faster (over-
driving between 5-32 rpm) than the inner shaft. When
the BOC (Fig. 29) is running under these conditions, at
low vehicle speeds the drag shoes and the cage keep the
rollers up on the left side (forward side) of the inner
shaft flats. This is what is known as ªoverrunning
mode.º Notice that when the clutch is in overrunning
mode, the rollers are spinning clockwise and with the
outer race, thus no torque is being transferred.
NOTE: Low speed, forward and reverse operation is
identical, just in opposite directions. (Fig. 29) shows
forward direction in reverse the rollers are on the other
side of the flats due to a reversal of the cage force.
TRANSIENT CONDITION (BOC LOCKED), FRONT
WHEEL SLIP, FORWARD DIRECTION
When the front wheels lose traction and begin to
slip, the propeller shaft and rear axle pinion speed
difference decreases to zero. At this point the input
shaft (cam) becomes the driving member of the BOC
(Fig. 30), compressing the rollers against the outer
race. This locks the input shaft with the outer race
and transmits torque to the housing of the viscous
coupler, that in turn transmits torque to the rear
axle pinion. It should also be noted that when the
device is locked, the inner shaft and the outer raceare rotating at the same speed. The rollers are
pinched at this point and will stay locked until a
torque reversal (no front wheel slip) occurs. When
locked, the viscous coupler slips during the torque
transfer and the amount of torque transferred is
dependent on the coupling characteristic and the
amount of front wheel slip.
Fig. 29 BOC Operation at Low Speeds With No
Front Wheel Slip
1 - CAGE
2 - ROLLER
3 - INPUT SHAFT
Fig. 30 BOC Operation with Front Wheel Slip
3 - 38 REAR DRIVELINE MODULERS
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
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