differential DODGE RAM 2002 Service Owner's Manual

(10) Apply a bead of red Mopar Silicone Rubber
Sealant or equivalent to the housing cover (Fig. 44).
CAUTION: If housing cover is not installed within 3
to 5 minutes, the cover must be cleaned and new
RTV applied or adhesion quality will be compro-
mised.
(11) Install the cover and tighten bolts in a criss-
cross pattern to 47 N´m (35 ft. lbs.).
(12) Fill the differential with Mopar Hypoid Gear
Lubricant or equivalent to bottom of the fill plug
hole.
(13) Install fill hole plug and tighten to 34 N´m (25
ft. lbs.).
(14) Remove support and lower vehicle.DIFFERENTIAL CASE
BEARINGS
REMOVAL
(1) Remove differential case from axle housing.
(2) Remove bearings from the differential case
with Puller/Press C-293-PA, Adapters C-293-62 and
Step Plate C-4487-1 (Fig. 45).
Fig. 44 DIFFERENTIAL COVER - TYPICAL
1 - SEALANT SURFACE
2 - SEALANT
3 - SEALANT THICKNESS
Fig. 45 Differential Bearing Removal
1 - PULLER
2 - ADAPTERS
3 - STEP PLATE
4 - BEARING
5 - DIFFERENTIAL CASE
3 - 40 FRONT AXLE - 248FBIBR/BE
DIFFERENTIAL (Continued)

INSTALLATION
(1) Install differential side bearings with Installer
C-4190 and Handle C-4171 (Fig. 46).
(2) Install differential case in axle housing.
PINION GEAR/RING GEAR
REMOVAL
NOTE: The ring and pinion gears are service in a
matched set. Do not replace the ring gear without
replacing the match pinion gear.
(1) Remove differential from housing.
(2) Place differential case in a vise with soft metal
jaw.
(3) Remove ring gear bolts from differential case.
(4) Drive ring gear from differential case with a
soft hammer (Fig. 47).
(5) Mark pinion yoke and propeller shaft for
installation alignment.(6) Remove propeller shaft from pinion yoke and
tie propeller shaft to underbody.
(7) Hold pinion yoke with Holder 6719A and
remove pinion yoke nut and washer.
(8) Remove pinion yoke with Puller C-452 and
Flange Wrench C-3281 (Fig. 48).
Fig. 46 Install Differential Side Bearings
1 - HANDLE
2 - DIFFERENTIAL CASE
3 - BEARING
4 - INSTALLER
Fig. 47 RING GEAR
1 - CASE
2 - RING GEAR
3 - HAMMER
Fig. 48 PINION YOKE
1 - FLANGE WRENCH
2 - YOKE
3 - PULLER
BR/BEFRONT AXLE - 248FBI 3 - 41
DIFFERENTIAL CASE BEARINGS (Continued)

(11) Install yoke washer and anewnut on the
pinion gear. Tighten the nut to 291 N´m (215 ft. lbs.)
minimum.Do not over±tighten.Maximum torque
is 678 N´m (500 ft. lbs.).
CAUTION: Never loosen pinion gear nut to decrease
pinion preload torque and never exceed specified
preload torque. If preload torque is exceeded a new
collapsible spacer must be installed.
(12) Use Yoke Holder 6719A to hold the yoke (Fig.
60) and tighten the nut in 6.8 N´m (5 ft. lbs.) until
the rotating torque is achieved. Measure the preload
torque frequently to avoid over-tightening the nut.
(13) Check bearing preload torque with an inch
pound torque wrench (Fig. 61). The torque to rotate
the pinion gear should be:
²Original Bearings: 1 to 2 N´m (10 to 20 in. lbs.).
²New Bearings: 2.26 to 4.52 N´m (20 to 40 in.
lbs.).
(14) Invert differential case in a vise and start two
ring gear bolts. This will provide case-to-ring gear
bolt hole alignment.
(15) Installnewring gear bolts and alternately
tighten to 176 N´m (130 ft. lbs.). (Fig. 62).
CAUTION: Never reuse the ring gear bolts. The
bolts can fracture causing extensive damage.
(16) Install differential in axle housing and verify
gear mesh and contact pattern. Refer to Adjustments
(Gear Contact Pattern).
(17) Install differential cover and fill with lubri-
cant.
Fig. 60 PINION NUT
1 - PINION FLANGE
2 - YOKE HOLDING
3 - DIFFERENTIAL HOUSING
Fig. 61 Pinion Rotating Torque
1 -TORQUE WRENCH
2 - PINION YOKE
Fig. 62 RING GEAR BOLT
1 - TORQUE WRENCH
2 - RING GEAR BOLT
3 - RING GEAR
4 - CASE
BR/BEFRONT AXLE - 248FBI 3 - 45
PINION GEAR/RING GEAR (Continued)

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)

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 - 48 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)

DIAGNOSTIC CHART
Condition Possible Causes Correction
Wheel Noise 1. Wheel loose. 1. Tighten loose nuts.
2. Faulty, brinelled wheel bearing. 2. Replace bearing.
Axle Shaft Noise 1. Misaligned axle tube. 1. Inspect axle tube alignment.
Correct as necessary.
2. Bent or sprung axle shaft. 2. Inspect and correct as necessary.
Axle Shaft Broke 1. Misaligned axle tube. 1. Replace the broken shaft after
correcting tube mis-alignment.
2 Vehicle overloaded. 2. Replace broken shaft and avoid
excessive weight on vehicle.
3. Erratic clutch operation. 3. Replace broken shaft and avoid
or correct erratic clutch operation.
4. Grabbing clutch. 4. Replace broken shaft and inspect
and repair clutch as necessary.
Differential Cracked 1. Improper adjustment of the
differential bearings.1. Replace case and inspect gears
and bearings for further damage.
Set differential bearing pre-load
properly.
2. Excessive ring gear backlash. 2. Replace case and inspect gears
and bearings for further damage.
Set ring gear backlash properly.
3. Vehicle overloaded. 3. Replace case and inspect gears
and bearings for further damage.
Avoid excessive vehicle weight.
4. Erratic clutch operation. 4. Replace case and inspect gears
and bearings for further damage.
Avoid erratic use of clutch.
Differential Gears Scored 1. Insufficient lubrication. 1. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
2. Improper grade of lubricant. 2. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
3. Excessive spinning of one
wheel/tire.3. Replace scored gears. Inspect all
gears, pinion bores, and shaft for
damage. Service as necessary.
BR/BEREAR AXLE - 248RBI 3 - 49
REAR AXLE - 248RBI (Continued)

Condition Possible Causes Correction
Loss Of Lubricant 1. Lubricant level too high. 1. Drain lubricant to the correct
level.
2. Worn axle shaft seals. 2. Replace seals.
3. Cracked differential housing. 3. Repair as necessary.
4. Worn pinion seal. 4. Replace seal.
5. Worn/scored yoke. 5. Replace yoke and seal.
6. Axle cover not properly sealed. 6. Remove, clean, and re-seal
cover.
Axle Overheating 1. Lubricant level low. 1. Fill differential to correct level.
2. Improper grade of lubricant. 2. Fill differential with the correct
fluid type and quantity.
3. Bearing pre-loads too high. 3. Re-adjust bearing pre-loads.
4. Insufficient ring gear backlash. 4. Re-adjust ring gear backlash.
Gear Teeth Broke 1. Overloading. 1. Replace gears. Examine other
gears and bearings for possible
damage.
2. Erratic clutch operation. 2. Replace gears and examine the
remaining parts for damage. Avoid
erratic clutch operation.
3. Ice-spotted pavement. 3. Replace gears and examine
remaining parts for damage.
4. Improper adjustments. 4. Replace gears and examine
remaining parts for damage. Ensure
ring gear backlash is correct.
Axle Noise 1. Insufficient lubricant. 1. Fill differential with the correct
fluid type and quantity.
2. Improper ring gear and pinion
adjustment.2. Check ring gear and pinion
contact pattern. Adjust backlash or
pinion depth.
3. Unmatched ring gear and pinion. 3. Replace gears with a matched
ring gear and pinion.
4. Worn teeth on ring gear and/or
pinion.4. Replace ring gear and pinion.
5. Loose pinion bearings. 5. Adjust pinion bearing pre-load.
6. Loose differential bearings. 6. Adjust differential bearing
pre-load.
7. Mis-aligned or sprung ring gear. 7. Measure ring gear run-out.
Replace components as necessary.
8. Loose differential bearing cap
bolts.8. Inspect differential components
and replace as necessary. Ensure
that the bearing caps are torqued
tot he proper specification.
9. Housing not machined properly. 9. Replace housing.
3 - 50 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)

REMOVAL
(1) Raise and support the vehicle.
(2) Position an axle lift under the axle and secure
it to the axle.
(3) Remove the wheels and tires.
(4) Remove RWAL sensor from the differential
housing, if necessary.
(5) Remove brake hose from the axle junction
block.
(6) Disconnect parking brake cables and cable
brackets.
(7) Remove vent hose from the axle shaft tube.
(8) Mark propeller shaft and yoke for installation
alignment reference.
(9) Remove propeller shaft.
(10) Remove shock absorbers from the axle brack-
ets.
(11) Remove spring clamps and spring brackets.
(12) Remove axle from the vehicle.
INSTALLATION
(1) Raise axle with lift and align to the leaf spring
centering bolts.
(2) Install spring clamps and spring brackets.
(3) Install shock absorbers and tighten to specifica-
tions.
(4) Install RWAL sensor to the differential hous-
ing, if necessary.
(5) Install parking brake cables and cable brackets
(6) Install brake hose to the axle junction block.
(7) Install axle vent hose.
(8) Install propeller shaft with reference marks
aligned.
(9) Install wheels and tires assemblies.
(10) Add gear lubricant, if necessary.
(11) Remove lift from the axle and lower the vehi-
cle.
ADJUSTMENTS
Ring and pinion gears are supplied as matched
sets only. The identifying numbers for the ring and
pinion gear are etched into the face of each gear (Fig.
4). A plus (+) number, minus (±) number or zero (0) is
etched into the face of the pinion gear. This number
is the amount (in thousandths of an inch) the depth
varies from the standard depth setting of a pinion
etched with a (0). The standard setting from the cen-
ter line of the ring gear to the back face of the pinion
is 127 mm (5.00 in.). The standard depth provides
the best gear tooth contact pattern. Refer to Back-
lash and Contact Pattern in this section for addi-
tional information.
Compensation for pinion depth variance is
achieved with a select shim. The shims are placed
between the rear pinion bearing and the pinion gear
head (Fig. 5).If a new gear set is being installed, note the depth
variance etched into both the original and replace-
ment pinion. Add or subtract this number from the
thickness of the original depth shim/oil slinger to
compensate for the difference in the depth variances.
Refer to the Depth Variance chart.
Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or
minus the amount needed.
Fig. 4 PINION GEAR ID NUMBERS
1 - PRODUCTION NUMBERS
2 - PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER
Fig. 5 SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM
2 - DIFFERENTIAL BEARING SHIM
BR/BEREAR AXLE - 248RBI 3 - 51
REAR AXLE - 248RBI (Continued)

Note the etched number on the face of the pinion
gear head (±1, ±2, 0, +1, +2, etc.). The numbers rep-
resent thousands of an inch deviation from the stan-
dard. If the number is negative, add that value to therequired thickness of the depth shims. If the number
is positive, subtract that value from the thickness of
the depth shim. If the number is 0 no change is nec-
essary.
PINION GEAR DEPTH VARIANCE
Original Pinion
Gear Depth
VarianceReplacement Pinion Gear Depth Variance
24232221 0 +1 +2 +3 +4
+4+0.008 +0.007 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 0
+3+0.007 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 020.001
+2+0.006 +0.005 +0.004 +0.003 +0.002 +0.001 020.00120.002
+1+0.005 +0.004 +0.003 +0.002 +0.001 020.00120.00220.003
0+0.004 +0.003 +0.002 +0.001 020.00120.00220.00320.004
21+0.003 +0.002 +0.001 020.00120.00220.00320.00420.005
22+0.002 +0.001 020.00120.00220.00320.00420.00520.006
23+0.001 020.00120.00220.00320.00420.00520.00620.007
24020.00120.00220.00320.00420.00520.00620.00720.008
PINION DEPTH MEASUREMENT AND ADJUSTMENT
Measurements are taken with pinion bearing cups
and pinion bearings installed in the housing. Take
measurements with Pinion Gauge Set and Dial Indi-
cator C-3339 (Fig. 6).
(1) Assemble Pinion Height Block 6739, Pinion
Block 6736 and rear pinion bearing onto Screw 6741
(Fig. 6).
(2) Insert assembled height gauge components,
rear bearing and screw into the housing through pin-
ion bearing cups (Fig. 7).
(3) Install front pinion bearing and Cone-nut 6740
hand tight (Fig. 6).
(4) Place Arbor Disc 6732 on Arbor D-115-3 in posi-
tion in the housing side bearing cradles (Fig. 8).
NOTE: Arbor Discs 6732 has different step diame-
ters to fit other axles. Choose proper step for axle
being serviced.
(5) Install differential bearing caps on arbor discs
and snug the bearing cap bolts. Then cross tighten
cap bolts to 108 N´m (80 ft. lbs.).
(6) Assemble Dial Indicator C-3339 into Scooter
Block D-115-2 and secure set screw.
(7) Position Scooter Block/Dial Indicator flush on
the pinion height block. Hold scooter block and zero
the dial indicator.
(8) Slowly slide the scooter block across the pinion
height block over to the arbor (Fig. 9). Move the
Fig. 6 PINION DEPTH GAUGE TOOLS
1 - DIAL INDICATOR
2 - ARBOR
3 - PINION HEIGHT BLOCK
4 - CONE
5 - SCREW
6 - PINION BLOCK
7 - SCOOTER BLOCK
8 - ARBOR DISC
3 - 52 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)