power DODGE RAM 2002 Service Repair Manual

GROUP TAB LOCATOR
Introduction
0Lubrication & Maintenance
2Suspension
3Differential & Driveline
5Brakes
6Clutch
7Cooling
8AAudio
8BChime/Buzzer
8EElectronic Control Modules
8FEngine Systems
8GHeated Systems
8HHorn
8IIgnition Control
8JInstrument Cluster
8LLamps
8MMessage Systems
8NPower Systems
8ORestraints
8PSpeed Control
8QVehicle Theft Security
8RWipers/Washers
8WWiring
9Engine
11Exhaust System
13Frame & Bumpers
14Fuel System
19Steering
21Transmission and Transfer Case
22Tires/Wheels
23Body
24Heating & Air Conditioning
25Emissions Control
Component and System Index
Service Manual Comment Forms (Rear of Manual)
NOTE: For New Vehicle Preparation
information, see the separate
publication, 81-170-00003.

VEHICLE EMISSION CONTROL
INFORMATION (VECI)
DESCRIPTION
Vehicles equipped with 5.9L V-8 LDC-gas powered
engines have a vehicle emission control information
(VECI) label.
The label combines both emission control informa-
tion and vacuum hose routing. This label is located
in the engine compartment in front of the radiator
(Fig. 3).
There are unique VECI labels for vehicles built for
sale in the country of Canada and Heavy Duty Cycle
(HDC) engines. Canadian labels are written in both
the English and French languages. For all Canadian
vehicles, the label is split into two different labels.
The VECI labels are permanently attached and
cannot be removed without defacing information and
destroying label.
The VECI label contains the following:
²Engine family and displacement
²Evaporative family
²Emission control system schematic
²Certification application
²Engine timing specifications (if adjustable)
²Idle speeds (if adjustable)
²Spark plug and gap
The 5.9L HDC-gas powered engine will have two
labels. One of the labels is located in front of the
radiator in the engine compartment (Fig. 3) and will
contain vacuum hose routing only. The other is
attached to the drivers side of the engine air cleaner
housing (Fig. 3).The VECI label for the 5.9L HDC-gas powered
engine will contain the following:
²Engine family and displacement
²Evaporative family
²Certification application
²Engine timing specifications (if adjustable)
²Idle speeds (if adjustable)
²Spark plug and gap
The label for the 8.0L V-10 HDC-gas powered
engine is also located in the engine compartment. It
is attached to a riveted metal plate located to the
right side of the generator (Fig. 4).
EQUIPMENT IDENTIFICATION
PLATE
DESCRIPTION
The Equipment Identification Plate (Fig. 5)is
located at the left, front of the inner hood panel. The
plate lists information concerning the vehicle as fol-
lows:
²The model.
²The wheelbase.
²The VIN (Vehicle Identification Number).
²The T.O.N. (order number).
²The optional and special equipment installed on
the vehicle.
Refer to the information listed on the plate when
ordering replacement parts.
Fig. 3 VECI Label Location
1 - VEHICLE EMISSION CONTROL INFORMATION (VECI) LABEL
2 - VECI LABEL (5.9L HDC FOR CANADA ONLY)
3 - VECI LABEL (5.9L HDC ONLY) (INCLUDES CANADA)
Fig. 4 VECI Label LocationÐ8.0L V-10 Engine
1 - VECI LABEL
2 - GENERATOR
BR/BEINTRODUCTION 3

DESCRIPTION - AUTOMATIC TRANSMISSION
FLUID
NOTE: Refer to the maintenance schedules in this
group for the recommended maintenance (fluid/filter
change) intervals for this transmission.
NOTE: Refer to Service Procedures in this group for
fluid level checking procedures.
MopartATF +4, type 9602, Automatic Transmis-
sion Fluid is the recommended fluid for
DaimlerChrysler automatic transmissions.
Dexron II fluid IS NOT recommended. Clutch
chatter can result from the use of improper
fluid.
MopartATF +4, type 9602, Automatic Transmis-
sion Fluid when new is red in color. The ATF is dyed
red so it can be identified from other fluids used in
the vehicle such as engine oil or antifreeze. The red
color is not permanent and is not an indicator of fluid
condition. As the vehicle is driven, the ATF will begin
to look darker in color and may eventually become
brown.This is normal.A dark brown/black fluid
accompanied with a burnt odor and/or deterioration
in shift quality may indicate fluid deterioration or
transmission component failure.
FLUID ADDITIVES
DaimlerChrysler strongly recommends against the
addition of any fluids to the transmission, other than
those automatic transmission fluids listed above.
Exceptions to this policy are the use of special dyes
to aid in detecting fluid leaks.
Various ªspecialº additives and supplements exist
that claim to improve shift feel and/or quality. These
additives and others also claim to improve converter
clutch operation and inhibit overheating, oxidation,
varnish, and sludge. These claims have not been sup-
ported to the satisfaction of DaimlerChrysler and
these additivesmust not be used.The use of trans-
mission ªsealersº should also be avoided, since they
may adversely affect the integrity of transmission
seals.
OPERATION - AUTOMATIC TRANSMISSION
FLUID
The automatic transmission fluid is selected based
upon several qualities. The fluid must provide a high
level of protection for the internal components by
providing a lubricating film between adjacent metal
components. The fluid must also be thermally stable
so that it can maintain a consistent viscosity through
a large temperature range. If the viscosity stays con-
stant through the temperature range of operation,transmission operation and shift feel will remain con-
sistent. Transmission fluid must also be a good con-
ductor of heat. The fluid must absorb heat from the
internal transmission components and transfer that
heat to the transmission case.
FLUID CAPACITIES
SPECIFICATIONS
FLUID CAPACITIES
DESCRIPTION SPECIFICATION
FUEL TANK
2500 Series Club Cab
and Quad Cab with 6.5'
Short Box129 L (34 gal.)*****
All 8' Long Box 132 L (35 gal.)*****
All Cab/Chassis Models 132 L (35 gal.)*****
ENGINE OIL WITH FILTER
5.9L 4.7 L (5.0 qts.)
8.0L 6.6 L (7.0 qts.)
5.9L DIESEL 10.4 L (11.0 qts.)
COOLING SYSTEM
5.9L 19 L (20 qts.)****
8.0L 24.5 L (26.0 qts.)****
5.9L DIESEL 22.7 L (24.0 qts.)****
POWER STEERING
Power steering fluid capacities are dependent on
engine/chassis options as well as steering gear/cooler
options. Depending on type and size of internal
cooler, length and inside diameter of cooler lines, or
use of an auxiliary cooler, these capacities may vary.
Refer to 19, Steering for proper fill and bleed
procedures.
AUTOMATIC TRANSMISSION
Service Fill - 46RE 3.8 L (4.0 qts.)
O-haul - 46RE 9-9.5L (19-20 pts.)*
Service Fill - 47RE 3.8 L (4.0 qts.)
O-haul - 47RE 14-16 L (29-33 pts.)*
0 - 6 LUBRICATION & MAINTENANCEBR/BE
FLUID TYPES (Continued)

FRONT AXLE - 248FBI
TABLE OF CONTENTS
page page
FRONT AXLE - 248FBI
DESCRIPTION.........................14
OPERATION...........................14
DIAGNOSIS AND TESTING - AXLE..........15
REMOVAL.............................18
INSTALLATION.........................18
ADJUSTMENTS........................19
SPECIFICATIONS
FRONT AXLE - 248FBI.................27
SPECIAL TOOLS
FRONT AXLE........................27
AXLE SHAFTS
REMOVAL.............................29
INSTALLATION.........................29
AXLE SHAFTS - INTERMEDIATE
REMOVAL.............................30
INSTALLATION - INTERMEDIATE AXLE......30
AXLE SHAFT SEALS
REMOVAL.............................31
INSTALLATION.........................31
AXLE VACUUM MOTOR
DESCRIPTION.........................31
OPERATION...........................31DIAGNOSIS AND TESTING - VACUUM MOTOR . 32
REMOVAL.............................34
DISASSEMBLY.........................34
ASSEMBLY............................34
INSTALLATION.........................34
SINGLE CARDAN UNIVERSAL JOINTS
REMOVAL.............................34
INSTALLATION.........................35
PINION SEAL
REMOVAL.............................35
INSTALLATION.........................35
DIFFERENTIAL
REMOVAL.............................37
DISASSEMBLY.........................38
ASSEMBLY............................38
INSTALLATION.........................39
DIFFERENTIAL CASE BEARINGS
REMOVAL.............................40
INSTALLATION.........................41
PINION GEAR/RING GEAR
REMOVAL.............................41
INSTALLATION.........................43
FRONT AXLE - 248FBI
DESCRIPTION
The Front Beam-design Iron (FBI) axle consists of a
cast iron center casting differential housing with axle
shaft tubes extending from each side. The tubes are
pressed into the differential housing and welded. The
axles is equipped with semi-floating axle shafts, mean-
ing that loads are supported by 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 cones and case. Pinion bearing pre-load is set and maintained by the use of a collapsible
spacer. The stamped steel cover provides a means for
inspection and servicing the differential.
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 rotates
the 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.
3 - 14 FRONT AXLE - 248FBIBR/BE

AXLE SHAFT SEALS
REMOVAL
(1) Remove hub bearings and axle shafts.
(2) Remove axle shaft seal from the differential
housing with a long drift or punch.Be careful not
to damage housing.
(3) Clean the inside perimeter of the differential
housing with fine crocus cloth.
INSTALLATION
(1) Apply a light film of oil to the inside lip of the
new axle shaft seal.
(2) Install the inner axle seal (Fig. 25).
(3) Install axles and hub bearings.
AXLE VACUUM MOTOR
DESCRIPTION
The disconnect axle control system consists of:
²Shift motor.
²Indicator switch.
²Vacuum switch.
²Vacuum harness (Fig. 26).
OPERATION
The shift motor receives a vacuum signal from the
switch mounted on the transfer case when the vehi-
cle operator wants to switch from two wheel drive
mode to four wheel drive mode, or vice versa. When
this signal is received, the shift motor begins to move
the shift fork and collar within the axle housing. In
the four wheel drive mode, the shift collar connects
the axle intermediate shaft to the axle shaft to sup-
ply engine power to both front wheels. In two wheel
drive mode, the shift collar is disengaged from the
intermediate shaft and the intermediate shaft is
allowed to free-spin. When the two shafts are disen-
gaged, the load on the engine is reduced, thereby pro-
viding better fuel economy and road handling.
Fig. 25 SEAL INSTALLATION
1 - DIFFERENTIAL HOUSING
2 - POSITION FOR OPEN-END WRENCH
3 - SPECIAL TOOL 5041-2
4 - SPECIAL TOOL 8417
5 - SEAL
6 - SPECIAL TOOL 8411
Fig. 26 VACUUM CONTROL SYSTEM
1 - CHECK VALVE
2 - CONTROL SWITCH ON TRANSFER CASE
3 - AIR VENT FILTER
4 - AXLE SHIFT MOTOR
5 - INDICATOR SWITCH
BR/BEFRONT AXLE - 248FBI 3 - 31

REAR AXLE - 248RBI
TABLE OF CONTENTS
page page
REAR AXLE - 248RBI
DESCRIPTION.........................46
OPERATION...........................46
DIAGNOSIS AND TESTING - AXLE..........47
REMOVAL.............................51
INSTALLATION.........................51
ADJUSTMENTS........................51
SPECIFICATIONS
REAR AXLE - 248RBI..................59
SPECIAL TOOLS
REAR AXLE - 248RBI..................59
AXLE SHAFTS
REMOVAL.............................62
INSTALLATION.........................62
AXLE BEARINGS
REMOVAL.............................62
INSTALLATION.........................62
PINION SEAL
REMOVAL.............................63INSTALLATION.........................63
DIFFERENTIAL
REMOVAL.............................64
DISASSEMBLY.........................65
ASSEMBLY............................66
INSTALLATION.........................66
DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING - TRAC-LOKT.....67
DISASSEMBLY.........................68
ASSEMBLY............................70
DIFFERENTIAL CASE BEARINGS
REMOVAL.............................72
INSTALLATION.........................72
PINION GEAR/RING GEAR/TONE RING
REMOVAL.............................73
INSTALLATION.........................75
REAR AXLE - 248RBI
DESCRIPTION
The Rear Beam-design Iron (RBI) axle housings consist
of an iron center casting (differential housing) with axle
shaft tubes extending from either side. The tubes are
pressed into the differential housing and welded. The
axles are equipped with full-floating axle shafts, meaning
that loads are supported by the axle housing tubes.
The differential case for the standard differentials
and the Trac-loktdifferential are a one-piece design.
Differential bearing preload and ring gear backlash
are adjusted by the use of shims located between the
differential bearing cones and case. Pinion bearing
preload is set and maintained by the use of a collaps-
ible spacer. The removable, stamped steel cover pro-
vides a means for inspection and service.
OPERATION
STANDARD DIFFERENTIAL
The axle receives power from the transmission/
transfer case through the rear propeller shaft. The
rear propeller shaft is connected to the pinion gear
which rotates the differential through the gear mesh
with the ring gear bolted to the differential case. The
engine power is transmitted to the axle shaftsthrough the pinion mate and side gears. The side
gears are splined to the axle shafts.
During straight-ahead driving, the differential pin-
ion 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
pinion mate shaft but do not rotate around it (Fig. 1).Fig. 1 STRAIGHT AHEAD DRIVING
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
3 - 46 REAR AXLE - 248RBIBR/BE

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.
TRAC-LOKTDIFFERENTIAL
The differential clutches are engaged by two con-
current forces. The first being the preload force
exerted through Belleville spring washers within the
clutch packs. The second is the separating forces gen-
erated by the side gears as torque is applied through
the ring gear (Fig. 3).
This design provides the differential action needed
for turning corners and for driving straight ahead
during periods of unequal traction. When one wheel
looses traction, the clutch packs transfer additional
torque to the wheel having the most traction. The
differential resist wheel spin on bumpy roads and
provide more pulling power when one wheel looses
traction. Pulling power is provided continuously until
both wheels loose traction. If both wheels slip due to
unequal traction, Trac-loktoperation is normal. In
extreme cases of differences of traction, the wheel
with the least traction may spin.
DIAGNOSIS AND TESTING - AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, incorrect pinion depth, toothcontact, worn/damaged gears, or the carrier housing
not having the proper offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
Fig. 2 DIFFERENTIAL ON TURNS
1 - PINION GEARS ROTATE ON PINION SHAFTFig. 3 TRAC-LOK LIMITED SLIP DIFFERENTIAL
1 - CASE
2 - RING GEAR
3 - DRIVE PINION
4 - PINION GEAR
5 - MATE SHAFT
6 - CLUTCH PACK
7 - SIDE GEAR
8 - CLUTCH PACK
BR/BEREAR AXLE - 248RBI 3 - 47
REAR AXLE - 248RBI (Continued)

REAR AXLE - 267RBI
TABLE OF CONTENTS
page page
REAR AXLE - 267RBI
DESCRIPTION.........................78
OPERATION...........................78
DIAGNOSIS AND TESTING - AXLE..........80
REMOVAL.............................82
INSTALLATION.........................82
ADJUSTMENTS........................83
SPECIFICATIONS
REAR AXLE - 267RBI..................91
SPECIAL TOOLS
REAR AXLE - 267RBI..................91
AXLE SHAFTS
REMOVAL.............................94
INSTALLATION.........................94
AXLE BEARINGS
REMOVAL.............................94
INSTALLATION.........................94
PINION SEAL
REMOVAL.............................94INSTALLATION.........................95
DIFFERENTIAL
REMOVAL.............................96
DISASSEMBLY.........................97
ASSEMBLY............................97
INSTALLATION.........................97
DIFFERENTIAL - POWR-LOK
DIAGNOSIS AND TESTING - POWR-LOKT....99
DISASSEMBLY.........................99
ASSEMBLY............................99
DIFFERENTIAL CASE BEARINGS
REMOVAL............................102
INSTALLATION........................102
PINION GEAR/RING GEAR/TONE RING
REMOVAL............................103
INSTALLATION........................104
REAR AXLE - 267RBI
DESCRIPTION
The Rear Beam-design Iron (RBI) axle housings
consist of an iron center casting (differential housing)
with axle shaft tubes extending from either side. The
tubes are pressed into the differential housing and
welded. The axles are full-floating axle shafts, sup-
ported by the axle housing tubes. The full-float shafts
are retained by bolts attached to the hub.
The differential case for the standard differential is
a one-piece design. Differential bearing preload and
ring gear backlash are adjusted by the use of shims
located between the differential bearing cones and
case. Pinion bearing preload is set and maintained by
the use of a solid shims. The differential cover pro-
vides a means for inspection and service.
Axles equipped with a Powr-loktdifferential are
optional. The differential has a two-piece differentialcase. The differential contains four pinion gears and
a two-piece pinion mate cross shaft to provide
increased torque to the non-slipping wheel through a
ramping motion in addition to the standard Trac-lokt
components.
OPERATION
STANDARD DIFFERENTIAL
The axle receives power from the transmission/
transfer case through the rear propeller shaft. The
rear propeller shaft is connected to the pinion gear
which rotates the 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.
3 - 78 REAR AXLE - 267RBIBR/BE

torque supplied to the non-slipping wheel. The differ-
ential resist wheel spin on bumpy roads and provide
more pulling power when one wheel looses traction.
Pulling power is provided continuously until both
wheels loose traction. If both wheels slip due to
unequal traction, operation is normal. In extreme
cases of differences of traction, the wheel with the
least traction may spin.
DIAGNOSIS AND TESTING - AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, incorrect pinion depth, tooth
contact, worn/damaged gears, or the carrier housing
not having the proper offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
cle turns. A worn pinion shaft can also cause a snap-
ping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side±gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).
²Worn or out-of-balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rearend vibra-
tion. Do not overlook engine accessories, brackets
and drive belts.
NOTE: All driveline components should be exam-
ined before starting any repair.
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
3 - 80 REAR AXLE - 267RBIBR/BE
REAR AXLE - 267RBI (Continued)

OPERATION
STANDARD DIFFERENTIAL
The axle receives power from the transmission/
transfer case through the rear propeller shaft. The
rear propeller shaft is connected to the pinion gear
which rotates the 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.
During straight-ahead driving, the differential pin-
ion 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
pinion 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.
TRAC-LOKŸ DIFFERENTIAL
The Trac-lokŸ clutches are engaged by two concur-
rent forces. The first being the preload force exerted
through Belleville spring washers within the clutch
packs. The second is the separating forces generatedby the side gears as torque is applied through the
ring gear (Fig. 3).
The Trac-lokŸ design provides the differential
action needed for turning corners and for driving
straight ahead during periods of unequal traction.
When one wheel looses traction, the clutch packs
transfer additional torque to the wheel having the
most traction. Trac-lokŸ differentials resist wheel
spin on bumpy roads and provide more pulling power
when one wheel looses traction. Pulling power is pro-
vided continuously until both wheels loose traction. If
both wheels slip due to unequal traction, Trac-lokŸ
operation is normal. In extreme cases of differences
of traction, the wheel with the least traction may
spin.
DIAGNOSIS AND TESTING - AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, incorrect pinion depth, tooth
contact, worn/damaged gears, or the carrier housing
not having the proper offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
Fig. 1 STRAIGHT AHEAD DRIVING
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 2 ON TURNS
1 - PINION GEARS ROTATE ON PINION SHAFT
3 - 108 REAR AXLE - 286RBIBR/BE
REAR AXLE - 286RBI (Continued)