2004 CHRYSLER VOYAGER wheels

REAR DRIVELINE MODULE
TABLE OF CONTENTS
page page
REAR DRIVELINE MODULE
DESCRIPTION.........................23
OPERATION...........................23
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - REAR
DRIVELINE MODULE NOISE.............24
DIAGNOSIS AND TESTING - REAR
DRIVELINE MODULE OPERATION........26
REMOVAL.............................26
DISASSEMBLY.........................27
ASSEMBLY............................29
INSTALLATION.........................33
SPECIFICATIONS - REAR DRIVELINE
MODULE............................34
SPECIAL TOOLS.......................34
BI-DIRECTIONAL OVERRUNNING CLUTCH
DESCRIPTION.........................34
OPERATION...........................36
DIFFERENTIAL ASSEMBLY
DESCRIPTION.........................39OPERATION...........................39
FLUID - DIFFERENTIAL ASSEMBLY
STANDARD PROCEDURE - DIFFERENTIAL
ASSEMBLY FLUID CHANGE.............40
FLUID - OVERRUNNING CLUTCH HOUSING
STANDARD PROCEDURE - OVERRUNNING
CLUTCH HOUSING FLUID CHANGE.......41
VISCOUS COUPLER
DESCRIPTION.........................41
OPERATION...........................42
TORQUE ARM
REMOVAL.............................44
INSTALLATION.........................44
INPUT FLANGE SEAL
REMOVAL.............................44
INSTALLATION.........................45
OUTPUT FLANGE SEAL
REMOVAL.............................45
INSTALLATION.........................46
REAR DRIVELINE MODULE
DESCRIPTION
The rear driveline module assembly (Fig. 1) con-
sists of four main components:
²Bi-Directional Overrunning Clutch (BOC)
²Viscous Coupling
²Differential Assembly
²Torque Arm
The viscous coupling and bi-directional overrun-
ning clutch are contained within an overrunning
clutch housing, which fastens to the differential
assembly. The overrunning clutch housing and differ-
ential assembly have unique fluid sumps, each
requiring their own type and capacity of fluid. The
overrunning clutch housing requires MopartATF+4
(Automatic Transmission FluidÐType 9602) or equiv-
alent. The differential assembly requires Mopart
80W-90 Gear and Axle Lubricant.
Driveline module service is limited to the following
components:
²Differential Assembly (serviced only as assem-
bly)
²Viscous Coupling
²Bi-Directional Overrunning Clutch (BOC)
²Overrunning Clutch Housing²Seals (Input Flange, Output Flange, Overrun-
ning Clutch Housing O-rings)
²Input Flange/Shield
²Torque Arm
²Vents
²Fasteners
OPERATION
The primary benefits of All Wheel Drive are:
²Superior straight line acceleration, and corner-
ing on all surfaces
²Better traction and handling under adverse con-
ditions, resulting in improved hill climbing ability
and safer driving.
The heart of the system is an inter-axle viscous
coupling. The vehicle retains predominantly front-
wheel drive characteristics, but the All Wheel Drive
capability takes effect when the front wheels start to
slip. Under normal level road, straight line driving,
100% of the torque is allocated to the front wheels.
The viscous coupling controls and distributes torque/
power to the rear wheels. The viscous coupling trans-
mits torque to the rear wheels in proportion of the
amount of the slippage at the front wheels. Thais
variable torque distribution is automatic with no
driver inputs required. The coupling is similar to a
multi-plate clutch. It consists of a series of closely
spaced discs, which are alternately connected to the
RSREAR DRIVELINE MODULE3-23

front and rear drive units. The unit is totally sealed
and partially filled with silicone fluid. There is no
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
²Wheel bearings
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
3 - 24 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)

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
3 - 26 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)

SPECIFICATIONS - REAR DRIVELINE MODULE
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Bolt, Driveline Module-to-Body 54 40 Ð
Bolt, Halfshaft-to-Ouput Flange 61 45 Ð
Bolt, Overrunning Clutch Housing-to-Differential 60 44 Ð
Bolt, Torque Arm-to-Differential Assembly 60 44 Ð
Bolt, Torque Arm Mount-to-Body 54 40 Ð
Nut, Input Flange 135 100 Ð
Plug, Differential Drain/Fill 35 26 Ð
Plug, Overrunning Clutch Housing Drain/Fill 30 22 Ð
Vent, Differential/Overrunning Clutch Housing 12 Ð 110
SPECIAL TOOLSBI-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 a
slippery 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
Tool 6958
Tool 8493
Tool 8802
3 - 34 REAR DRIVELINE MODULERS
REAR DRIVELINE MODULE (Continued)

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 thetime. 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.
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 MODULE3-35
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)

OPERATION
In order to achieve all-wheel drive operation in
reverse, the overrunning clutch locking functional
direction must be reversible. The bi-directional over-
running clutch (BOC) changes the operational mode
direction depending on the propeller shaft direction.
The propeller shaft rotates in the clockwise (when
viewed from the front) direction when the vehicle is
moving forward, which indexes the BOC to the for-
ward overrunning position. When the vehicle is in
reverse, the propeller shaft will rotate counter-clock-
wise 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 dif-
ferentials. In this condition, the outer race is always
spinning faster (overdriving 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 race
are 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
3 - 36 REAR DRIVELINE MODULERS
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)

(5) Re-position the drain pan under the differential
fill plug.
(6) Remove the differential fill plug (Fig. 41).
(7) Using a suction gun (Fig. 42) or equivalent, fill
the differential assembly with 0.7 L (1.48 pts.) of
MopartGear and Axle Lubricant (80W-90).
(8) Install the fill plug and torque to 35 N´m (26 ft.
lbs.).
FLUID - OVERRUNNING
CLUTCH HOUSING
STANDARD PROCEDURE - OVERRUNNING
CLUTCH HOUSING FLUID CHANGE
(1) Raise vehicle on hoist.
(2) Position a drain pan under overrunning clutch
housing drain plug.
(3) Remove overrunning clutch housing drain plug
and drain fluid (Fig. 43).
(4) Install the drain plug and torque to 30 N´m (22
ft. lbs.).
(5) Re-position the drain pan under the overrun-
ning clutch housing fill plug.
(6) Remove fill plug (Fig. 44).
(7) Using a suction gun (Fig. 45), add 0.58 L (1.22
pts.) of MopartATF+4 (Automatic Transmission Flu-
idÐType 9602).
(8) Install fill plug and torque to 30 N´m (22 ft.
lbs.).
VISCOUS COUPLER
DESCRIPTION
The heart of the all-wheel drive system is the
inter-axle viscous coupling and bi-directional over-
running clutch. Under normal driving the vehicle
retains predominantly front wheel drive characteris-
tics. The all-wheel drive takes effect when the front
wheels start to slip. Under normal level road,
straight line driving, 100% of the torque is allocated
to the front wheels. The viscous coupler allows more
Fig. 42 Filling Differential
1 - DIFFERENTIAL ASSEMBLY
2 - SUCTION GUN
Fig. 43 Overrunning Clutch Case Drain Plug
1 - OVERRUNNING CLUTCH HOUSING DRAIN PLUG
Fig. 44 Overrunning Clutch Housing Fill Plug
1 - OVERRUNNING CLUTCH HOUSING FILL PLUG
2 - FUEL TANK
RSREAR DRIVELINE MODULE3-41
FLUID - DIFFERENTIAL ASSEMBLY (Continued)

torque to the rear wheels in accordance with the
amount of slippage at the front wheels. The variable
torque distribution is automatic with no driver
inputs required.
OPERATION
The viscous coupler (Fig. 46) is a housing nearly
filled with a high viscosity silicone liquid and thin
metal plates alternately splined to an inner and
outer drum. The viscous coupler provides torque in
the following modes:²Shear mode (normal operation)
²Hump mode (locked mode)
The inner plates are slotted around the radius and
the outer plates have holes in them. In the shear
mode (normal operation), the plates are evenly
spaced and the torque is created by the shearing of
the plates through the fluid and 90-100% of the
torque is applied to the rear axle. During the shear
mode, a fluid flow pattern is created from this design
(holes and slots). This fluid flow causes high pressure
on each side of each pair of plates and low pressure
between each pair of plates.
When a high speed difference (shear) occurs
because of loss of traction (one axle spinning faster
than the other), the silicone fluid expands as it heats
from this shearing. When the silicone expands to fill
the viscous coupler completely, this pressure differ-
ence is high enough to squeeze each pair of plates
together. The resulting hump torque is up to 8 times
higher than the shear torque. When the viscous cou-
pler is in the hump mode, it does not lock the axles
(undifferentiated 4-Wheel Drive). It controls the
amount of slippage while delivering maximum power
to the axle having greatest traction. Once the speed
difference equalizes the fluid and plates cool down
and the viscous coupler goes back to the shear mode.
Fig. 45 Filling Overrunning Clutch Case
1 - OVERRUNNING CLUTCH HOUSING FILL HOLE
2 - SUCTION GUN
3 - 42 REAR DRIVELINE MODULERS
VISCOUS COUPLER (Continued)