1998 DODGE RAM 1500 rear axle

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)

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
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. 5).(1) Assemble Pinion Height Block 6739, Pinion
Block 8542 and rear pinion bearing onto Screw 6741
(Fig. 5).
(2) Insert assembled height gauge components,
rear bearing, and screw into the housing through
pinion bearing cups (Fig. 6).
(3) Install front pinion bearing and Cone-Nut 6740
onto the screw. Tighten cone-nut until Torque To
Rotate the screw is 1.7 N´m (15 in. lbs.) (Fig. 5).
Fig. 5 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
Fig. 6 PINION HEIGHT BLOCK
1 - PINION BLOCK
2 - PINION HEIGHT BLOCK
DRREAR AXLE - 9 1/4 3 - 85
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)

²Ring gear too far away from pinion gear (Fig.
11). Decrease backlash, by moving the ring closer to
the pinion gear using the adjusters.
²Ring gear too close to pinion gear (Fig. 12).
Increase backlash, by moving the ring away from the
pinion gear using the adjusters.
²Ring gear too far away from pinion gear (Fig.
13). Decrease backlash, by moving the ring closer to
the pinion gear using the adjusters.
²Ring gear too close to pinion gear (Fig. 14).
Increase backlash, by moving the ring away from the
pinion gear using the adjusters.
²Pinion gear set too low (Fig. 15). Increase pinion
gear height, by increasing the pinion depth shim
thickness.
²Pinion gear set too high (Fig. 16). Decrease pin-
ion depth, by decreasing the pinion depth shim thick-
ness.
Fig. 11 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
Fig. 12 INCORRECT BACKLASH
1 - DRIVE SIDE TOE
2 - COAST SIDE HEEL
Fig. 13 INCORRECT BACKLASH
1 - DRIVE SIDE HEEL
2 - COAST SIDE HEEL
Fig. 14 INCORRECT BACKLASH
1 - DRIVE SIDE TOE
2 - COAST SIDE TOE
Fig. 15 LOW PINION HEIGHT
3 - 88 REAR AXLE-91/4DR
REAR AXLE - 9 1/4 (Continued)

SIDE GEAR CLEARANCE
When measuring side gear clearance, check each
gear independently. If it necessary to replace a side
gear, replace both gears as a matched set.
(1) Install the axle shafts and C-locks and pinion
mate shaft.
(2) Measure each side gear clearance. Insert a
matched pair of feeler gauge blades between the gear
and differential housing on opposite sides of the hub
(Fig. 17).(3) If side gear clearances is no more than 0.005
inch. Determine if the axle shaft is contacting the
pinion mate shaft.Do not remove the feeler
gauges, inspect the axle shaft with the feeler
gauge inserted behind the side gear.If the end of
the axle shaft is not contacting the pinion mate
shaft, the side gear clearance is acceptable.
(4) If clearance is more than 0.005 inch (axle shaft
not contacting mate shaft), record the side gear clear-
ance. Remove the thrust washer and measure its
thickness with a micrometer. Add the washer thick-
ness to the recorded side gear clearance. The sum of
gear clearance and washer thickness will determine
required thickness of replacement thrust washer
(Fig. 18).
In some cases, the end of the axle shaft will move
and contact the mate shaft when the feeler gauge is
inserted. The C-lock is preventing the side gear from
sliding on the axle shaft.
(5) If there is no side gear clearance, remove the
C-lock from the axle shaft. Use a micrometer to mea-
sure the thrust washer thickness. Record the thick-
ness and re-install the thrust washer. Assemble the
differential case without the C-lock installed and re-
measure the side gear clearance.
(6) Compare both clearance measurements. If the
difference is less than 0.012 inch (0.305 mm), add
clearance recorded when the C-lock was installed to
thrust washer thickness measured. The sum will
determine the required thickness of the replacement
thrust washer.
(7) If clearance is 0.012 inch (0.305 mm) or
greater, both side gears must be replaced (matched
set) and the clearance measurements repeated.
(8) If clearance (above) continues to be 0.012 inch
(0.305 mm) or greater, the case must be replaced.
Fig. 16 HIGH PINION HEIGHT
Fig. 17 SIDE GEAR CLEARANCE
1 - FEELER GAUGE
2 - SIDE GEAR
Fig. 18 SIDE GEAR CALCULATIONS
DRREAR AXLE - 9 1/4 3 - 89
REAR AXLE - 9 1/4 (Continued)

SPECIFICATIONS
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.21, 3.55, 3.92
Differential Case Flange Runout 0.076 mm (0.003 in.)
Differential Case Clearance 0.12 mm (0.005 in.)
Ring Gear Diameter 235 mm (9.25 in.)
Ring Gear Backlash 0.12-0.20 mm (0.005-0.008 in.)
Ring Gear Runout 0.12 mm (0.005 in.)
Pinion Bearing Preload - New Bearings 1.7-4 N´m (15-35 in. lbs.)
Pinion Bearing Preload - Original Bearings 1-2 N´m (10-20 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Differential Cover Bolts 41 30 -
Bearing Cap Bolts 136 100 -
Ring Gear Bolts 157 115 -
Pinion Nut Minimum 285 210 -
Adjuster Lock Screw 10 7.5 90
Backing Plate Bolts 65 48 -
Pinion Mate Shaft Lock
Screw11 8 -
Axle U-Bolt Nuts 149 110 -
SPECIAL TOOLS
PULLER C-293-PA
PLUG C-293-3
ADAPTERS C-293-37
ADAPTERS C-293-47
3 - 90 REAR AXLE-91/4DR
REAR AXLE - 9 1/4 (Continued)