1998 DODGE RAM 1500 Rear differential

(8) Slowly slide the scooter block across the pinion
height block over to the arbor (Fig. 9). Move scooter
block till dial indicator crests the arbor, then record
the highest reading.
(9) Select a shim equal to the dial indicator read-
ing.
(10) Install the select shim between the rear pin-
ion bearing and the pinion gear head.
DIFFERENTIAL CASE BEARING PRELOAD AND
GEAR BACKLASH
Backlash is adjusted by moving the adjusters in
and out or both. By moving the adjusters the case/
ring gear will move closer or further away from the
pinion. In most cases this adjustment can be used to
achieve the correct gear tooth pattern and set the
case bearing preload.
(1) Remove adjuster lock bolts and adjuster locks
(Fig. 10).
(2) Loosen the differential bearing caps.
(3) Slide differential case toward the pinion gear
until the gears make contact/zero backlash. If zero
backlash cannot be obtained, turn the pinion side
adjuster until zero backlash is obtained.
(4) Holding the differential case toward the pinion
gear, turn bearing adjusters with Spanner Wrench
8883 until they make contact with the differential
bearings/cups.
(5) Back off the ring gear side adjuster 4 holes, to
obtain initial ring gear backlash.
(6) Install ring gear side adjuster lock and bolt. Do
not tighten adjuster lock bolt at this time.
(7) Tighten pinion gear side adjuster firmly
against the differential case bearing cup.
(8) Rotate the pinion several times to seat the dif-
ferential bearings.
Fig. 8 GAUGE TOOLS IN HOUSING
1. PINION HEIGHT BLOCK
2. PINION BLOCK
3. ARBOR
4. ARBOR DISCS
Fig. 9 PINION DEPTH MEASUREMENT
1. DIAL INDICATOR
2. ARBOR
3. SCOOTER BLOCK
Fig. 10 ADJUSTER LOCK BOLT
1 - DIFFERENTIAL CASE
2 - ADJUSTER LOCK
3 - ADJUSTER LOCK BOLT
4 - BEARING CAP BOLT
3 - 60 FRONT AXLE - 9 1/4 AADR
FRONT AXLE - 9 1/4 AA (Continued)

(3) Install pinion depth shim (Fig. 52) on the pin-
ion gear shaft.
(4) Install rear pinion bearing (Fig. 53) with
Installer C-3095-A and a press.(5) Installnewcollapsible spacer (Fig. 54).
(6) Lubricate pinion and bearings.
(7) Install pinion into the housing and place front
pinion bearing onto the pinion shaft. Draw the pinion
shaft into the front bearing with Installer 8982 (Fig.
55).
Fig. 52 PINION DEPTH SHIM
1 - PINION DEPTH SHIM
2 - PINION GEAR
Fig. 53 REAR PINION BEARING
1 - PRESS
2 - INSTALLER
3 - PINION GEAR
4 - REAR PINION BEARING
Fig. 54 COLAPSIBLE SPACER
1 - COLAPSIBLE SPACER
2 - PINION GEAR
3 - REAR PINION BEARING
Fig. 55 PINION GEAR INSTALLER
1 - INSTALLER
2 - DIFFERENTIAL HOUSING
3 - 78 FRONT AXLE - 9 1/4 AADR
PINION GEAR/RING GEAR (Continued)

REAR AXLE-91/4
TABLE OF CONTENTS
page page
REAR AXLE-91/4
DIAGNOSIS AND TESTING................80
REMOVAL.............................83
INSTALLATION.........................83
ADJUSTMENTS........................83
SPECIFICATIONS.......................90
SPECIAL TOOLS.......................90
AXLE SHAFTS
REMOVAL.............................93
INSTALLATION.........................94
AXLE SHAFT SEALS
REMOVAL.............................94
INSTALLATION.........................94
AXLE BEARINGS
REMOVAL.............................95
INSTALLATION.........................95
PINION SEAL
REMOVAL.............................95
INSTALLATION.........................96
DIFFERENTIAL COVER
REMOVAL.............................97INSTALLATION.........................97
DIFFERENTIAL
REMOVAL.............................97
DISASSEMBLY.........................98
ASSEMBLY............................99
INSTALLATION.........................99
DIFFERENTIAL-TRAC-LOK
DESCRIPTION........................100
OPERATION..........................100
DIAGNOSIS AND TESTING...............100
DISASSEMBLY........................101
ASSEMBLY...........................103
DIFFERENTIAL CASE BEARINGS
REMOVAL............................105
INSTALLATION........................106
PINION GEAR/RING GEAR/TONE RING
REMOVAL............................106
INSTALLATION........................108
REAR AXLE-91/4
DIAGNOSIS AND TESTING
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 check for:
²Insufficient 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 bearingshave 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.
Differential bearingsusually produce a low pitch
noise. Differential bearing noise is similar to pinion
bearing noise. The pitch of differential bearing noise
is also constant and varies only with vehicle speed.
Axle shaft bearingsproduce 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.
3 - 80 REAR AXLE-91/4DR

Condition Possible Causes Correction
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.
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.
3 - 82 REAR AXLE-91/4DR
REAR AXLE - 9 1/4 (Continued)

Condition Possible Causes Correction
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.
REMOVAL
(1) Raise and support the vehicle.
(2) Position a lift under axle and secure axle to
lift.
(3) Remove wheels and tires assemblies.
(4) Remove all brake components.
(5) Remove axle vent hose.
(6) Mark propeller shaft and companion flange for
installation alignment reference.
(7) Remove propeller shaft.
(8) Remove shock absorbers from axle (Fig. 1).
(9) Remove U-bolts from axle (Fig. 2).
(10) Remove axle from the vehicle.
INSTALLATION
(1) Raise axle with lift and align to the leaf spring
centering bolts.(2) Install axle U-bolts and tighten to 149 N´m
(110 ft. lbs.).
(3) Install shock absorbers to axle and tighten to
specification.
(4) Install all brake comonents.
(5) Install axle vent hose.
(6) Align propeller shaft and pinion companion
flange reference marks and tighten companion flange
bolts to 115 N´m (85 ft. lbs.).
(7) Install the wheels and tires.
(8) Fill differential to specifications.
(9) Remove lift from axle and lower the vehicle.
ADJUSTMENTS
Ring gear and pinion are supplied as matched sets.
Identifying numbers for the ring gear and pinion are
painted onto the pinion gear shaft (Fig. 3) and the
side of the ring gear. A plus (+) number, minus (±)
DRREAR AXLE - 9 1/4 3 - 83
REAR AXLE - 9 1/4 (Continued)

number or zero (0) along with the gear set sequence
number (01 to 99) is on each gear. This first number
is the amount (in thousandths of an inch) the depth
varies from the standard depth setting of a pinion
marked with a (0). The next two numbers are the
sequence number of the gear set. The standard depth
provides the best teeth contact pattern.Compensation for pinion depth variance is
achieved with select shims. The shims are placed
behind the rear pinion bearing. (Fig. 4).
If installing a new gear, note the depth variance
number of the original and replacement pinion. Add
or subtract this number from the original depth
shim/oil slinger to compensate for the difference in
the depth variances. The numbers represent thou-
sands of an inch deviation from the standard. If the
number is negative, add that value to the required
thickness of the depth shims. If the number is posi-
tive, subtract that value from the thickness of the
depth shim.
Pinion Gear Depth Variance Chart: Note where
Old and New Pinion Marking columns intersect.
Intersecting figure represents plus or minus the
amount needed.
Fig. 1 SHOCK ABSORBER
1 - NUT
2 - AXLE
3 - SHOCK ABSORBER
Fig. 2 REAR SPRING
1 - LEAF SPRING
2 - PLATE
3 - NUTS
4 - FRONT NUT & BOLT
5 - SPRING CLAMP BOLTS
6 - SHACKLES
Fig. 3 PINION ID NUMBER
1 - VARIANCE NUMBER
2 - SEQUENCE NUMBER
Fig. 4 ADJUSTMENT SHIM LOCATIONS
1 - DIFFERENTIAL HOUSING
2 - COLLAPSIBLE SPACER
3 - PINION BEARING
4 - PINION DEPTH SHIM
5 - PINION GEAR
6 - BEARING CUP
3 - 84 REAR AXLE-91/4DR
REAR AXLE - 9 1/4 (Continued)

(4) Place Arbor Disc 8541 on Arbor D-115-3 in posi-
tion in the housing side bearing cradles (Fig. 7).
Install differential bearing caps on arbor discs and
tighten cap bolts to 41 N´m (30 ft. lbs.).
NOTE: Arbor Discs 8541 has different step diame-
ters to fit other axles. Choose proper step for axle
being serviced.
(5) Assemble Dial Indicator C-3339 into Scooter
Block D-115-2 and secure set screw.
(6) Place Scooter Block/Dial Indicator in position
in axle housing so dial probe and scooter block are
flush against the rearward surface of the pinion
height block (Fig. 5). Hold scooter block in place and
zero the dial indicator. Tighten dial indicator face
lock screw.
(7) Slide the dial indicator probe across the gap
between the pinion height block and the arbor bar
with the scooter block against the pinion height block
(Fig. 8). Continue moving the dial probe to the crest
of the arbor bar and record the highest reading.
(8) Select a shim equal to the dial indicator read-
ing plus the drive pinion gear depth variance number
marked on the shaft of the pinion. For example, if
the depth variance is ±2, add +0.002 in. to the dial
indicator reading.
DIFFERENTIAL BEARING PRELOAD AND GEAR
BACKLASH
The following must be considered when adjusting
bearing preload and gear backlash:
²The maximum ring gear backlash variation is
0.076 mm (0.003 in.).
²Mark the gears so the same teeth are meshed
during all backlash measurements.
²Maintain the torque while adjusting the bearing
preload and ring gear backlash.
²Excessive adjuster torque will introduce a high
bearing load and cause premature bearing failure.
Insufficient adjuster torque can result in excessive
differential case free-play and ring gear noise.
²Insufficient adjuster torque will not support the
ring gear correctly and can cause excessive differen-
tial case free-play and ring gear noise.
NOTE: The differential bearing cups will not always
immediately follow the threaded adjusters as they
are moved during adjustment. To ensure accurate
bearing cup responses to the adjustments:
²Maintain the gear teeth engaged (meshed) as
marked.
²The bearings must be seated by rapidly rotat-
ing the pinion gear a half turn back and forth.
²Do this five to ten times each time the threaded
adjusters are adjusted.
Fig. 7 PINION DEPTH TOOLS
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
Fig. 8 PINION GEAR DEPTH MEASUREMENT
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
3 - 86 REAR AXLE-91/4DR
REAR AXLE - 9 1/4 (Continued)

(1) Through the axle tube use Wrench C-4164 to
adjust each threaded adjuster inward until the differ-
ential bearing free-play is eliminated. Allow some
ring gear backlash approximately 0.25 mm (0.01 in.)
between the ring and pinion gear. Seat the bearing
cups with the procedure described above.
(2) Install dial indicator and position the plunger
against the drive side of a ring gear tooth (Fig. 9).
Measure the backlash at 4 positions, 90 degrees
apart around the ring gear. Locate and mark the
area of minimum backlash.
(3) Rotate the ring gear to the position of the least
backlash. Mark the gear so that all future backlash
measurements will be taken with the same gear
teeth meshed.
(4) Loosen the right-side, tighten the left-side
threaded adjuster. Obtain backlash of 0.076 to 0.102
mm (0.003-0.004 in.) with each adjuster tightened to
14 N´m (10 ft. lbs.). Seat the bearing cups with the
procedure described above.
(5) Tighten the differential bearing cap bolts 136
N´m (100 ft. lbs.).
(6) Tighten the right-side threaded adjuster to 102
N´m (75 ft. lbs.). Seat the bearing cups with the pro-
cedure described above. Continue to tighten the
right-side adjuster and seat bearing cups until the
torque remains constant at 102 N´m (75 ft. lbs.)
(7) Measure the ring gear backlash. The range of
backlash is 0.15 to 0.203 mm (0.006 to 0.008 in.).(8) Continue increasing the torque at the right-
side threaded adjuster until the specified backlash is
obtained.
NOTE: The left-side threaded adjuster torque
should have approximately 102 N´m (75 ft. lbs.). If
the torque is considerably less, the complete
adjustment procedure must be repeated.
(9) Tighten the left-side threaded adjuster until
102 N´m (75 ft. lbs.) torque is indicated. Seat the
bearing rollers with the procedure described above.
Do this until the torque remains constant.
(10) Install the threaded adjuster locks and
tighten the lock screws to 10 N´m (90 in. lbs.).
GEAR CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor-
rect running position of the ring and pinion gears.
This will produce low noise and long gear life. Gears
which are not positioned properly may be noisy and
have shorten gear life.
(1) Wipe clean each tooth of the ring gear.
(2) Apply gear marking compound to all of the ring
gear teeth.
(3) Verify bearing cap bolts are torque specifica-
tion.
(4) Apply parking brakes lightly to create at 14
N´m (10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:
²Gear contact pattern is correct (Fig. 10). Back-
lash and pinion depth is correct.
Fig. 9 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
3 - EXCITER RING
Fig. 10 CORRECT CONTACT PATTERN
DRREAR AXLE - 9 1/4 3 - 87
REAR AXLE - 9 1/4 (Continued)