1998 DODGE RAM 1500 Rear differential

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. 7).
(2) Loosen the differential bearing caps.
(3) Slide differential case toward the pinion gear
until the gears make contact/zero backlash. If zerobacklash 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 (Fig. 8) until they make contact with the differ-
ential bearings/cups.
(5) Back off the ring gear side adjuster 4 holes, to
obtain initial ring gear backlash.
Fig. 5 GAUGE TOOLS IN HOUSING
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
Fig. 6 PINION GEAR DEPTH MEASUREMENT
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
Fig. 7 ADJUSTER LOCK BOLT
1 - DIFFERENTIAL CASE
2 - ADJUSTER LOCK
3 - ADJUSTER LOCK BOLT
4 - BEARING CAP BOLT
Fig. 8 ADJUSTER SPANNER WRENCH
1 - WRENCH
2 - DIFFERENTIAL
DRREAR AXLE - 11 1/2 AA 3 - 145
REAR AXLE - 11 1/2 AA (Continued)

(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 def-
erential bearings.
(9) Loosen pinion gear side adjuster until it is no
longer in contact with the bearing cup, then tighten
it until it makes contact.
(10) Tighten pinion gear side adjuster an addi-
tional:
²New Bearings:6 Adjuster Holes
²Original Bearings:4 Adjuster Holes
(11) Install pinion gear side adjuster lock and bolt.
Do not tighten adjuster lock bolt at this time.
(12) Tighten bearing cap bolts to 115 N´m (85 ft.
lbs.).
(13) Tighten adjuster lock bolts to 33 N´m (24 ft.
lbs.).
(14) Measure ring gear backlash with a Dial Indi-
cator C-3339 and Dial Indicator Stud L-4438 at eight
points around the drive side of the ring gear (Fig. 9).
The backlash should be 0.08-0.25 mm (0.003-0.010
in) with a preferred backlash of 0.13-0.18 mm (0.005-
0.007 in).
NOTE: Backlash measurement should not vary
more than 0.05 mm (0.002 in) between measuring
points. If measurement does vary inspect the gears
for burrs, the differential case flange and ring gear
mounting.GEAR TOOTH 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 correct (Fig. 10). Backlash
and pinion depth is correct.
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.
Fig. 9 RING GEAR BACKLASH
1 - DIAL INDICATOR
2 - RING GEAR
Fig. 10 CORRECT CONTACT PATTERN
Fig. 11 INCORRECT BACKLASH
1 - COAST SIDE TOE
2 - DRIVE SIDE HEEL
3 - 146 REAR AXLE - 11 1/2 AADR
REAR AXLE - 11 1/2 AA (Continued)

SPECIFICATIONS
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.73, 4.10
Ring Gear Diameter 292 mm (11.5 in.)
Ring Gear Backlash 0.13-0.18 mm (0.005-0.007 in.)
Pinion Bearing Preload - New Bearings 1.69-2.82 N´m (15-25 in. lbs.)
Pinion Bearing Preload - Original Bearings 1-2 N´m (10-20 in. lbs.)
Pinion Bearing Preload + Differential Case Bearing
Preload - New Bearing3.4-5.6 N´m (30-50 in. lbs.)
Pinion Bearing Preload + Differential Case Bearing
Preload - Original Bearing2.8-5.1 N´m (25-45 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Fill Hole Plug 32 24 -
Differential Cover Bolts 40 30 -
Bearing Cap Bolts 281 207 -
Ring Gear Bolts 237 175 -
Axle Flange Bolts 129 95 -
Adjuster Lock Bolt 25 18 -
SPECIAL TOOLS
DIAL INDICATOR SET C-3339
HANDLE C-4171
BEARING INSTALLER D-389
3 - 148 REAR AXLE - 11 1/2 AADR
REAR AXLE - 11 1/2 AA (Continued)

(7) Remove pinion flange with Pinion Flange
Puller 8992 (Fig. 24).
(8) Remove pinion shaft seal with a pry tool or
slide hammer mounted screw.
INSTALLATION
(1) Installnewpinion seal with Installer 8896
(Fig. 25).
(2) Apply a light coat of teflon sealant to the pin-
ion flange splines.
(3) Lightly tap the pinion flange onto the pinion
until a few threads are showing.
(4) Install flange washer andnewpinion nut.(5) Hold pinion flange with Flange Wrench 8979
(Fig. 26) and tighten pinion nut until pinion end play
is taken up.
(6) Rotate pinion several times to seat bearings.
(7) Measure pinion rotating torque with an inch
pound torque wrench and compare it to recorded
measurement. Tighten pinion nut in small incre-
ments, until pinion rotating torque is 0.40-0.57 N´m
(3-5 in. lbs.) greater than recorded measurement.
(8) Rotate pinion several times then verify pinion
rotating torque again.
(9) Install axle shafts.
(10) Install propeller shaft with reference marks
aligned.
(11) Check differential fluid level.
Fig. 23 FLANGE WRENCH
1 - PINION FLANGE
2 - FLANGE WRENCH
Fig. 24 PINION FLANGE PULLER
1 - PINION FLANGE
2 - PULLER
Fig. 25 PINION SEAL INSTALLER
1 - HANDLE
2 - INSTALLER
Fig. 26 FLANGE WRENCH
1 - FLANGE WRENCH
2 - PINION FLANGE
3 - 154 REAR AXLE - 11 1/2 AADR
PINION SEAL (Continued)

DIFFERENTIAL
REMOVAL
(1) Remove fill hole plug from the differential
housing cover.
(2) Remove differential housing cover and drain
the lubricant.
(3) Remove axle shafts.
(4) Remove adjuster lock bolts and adjuster locks
(Fig. 27).
(5) Mark bearing caps left and right for installa-
tion reference.
(6) Remove bearing cap bolts and remove bearing
caps.
(7) Loosen differential bearing adjusters (Fig. 28)
with Spanner Wrench 8883.
(8) Remove differential case from the housing.
(9) Remove bearing cups and tag them left and
right for installation reference.
DISASSEMBLY
(1) Remove ring gear.
(2) Remove pinion shaft with a hammer and punch
from the side with the hole in the pinion shaft (Fig.
29).
Fig. 27 ADJUSTER LOCKS
1 - LOCK BOLT
2 - ADJUSTER LOCK
3 - ADJUSTER
4 - BEARING CAP
Fig. 28 ADJUSTERS
1 - BEARING CUP
2 - ADJUSTER
3 - BEARING CUP
4 - ADJUSTER
Fig. 29 PINION SHAFT
1 - PINION GEAR
2 - PINION SHAFT
3 - EXCITER RING
DRREAR AXLE - 11 1/2 AA 3 - 155

(3) Rotate one pinion gear with thrust washer
(Fig. 30) to the differential window and remove the
gear.
(4) Rotate the other pinion gear with thrust
washer (Fig. 31) to the differential window and
remove the gear.
(5) Remove differential side gears and thrust
washers (Fig. 32).
ASSEMBLY
NOTE: If the same gears and thrust washers are
being used, install them into their orignial locations.
(1) Lubricate all differential components with axle
lubricant.
(2) Install differential side gears and thrust wash-
ers (Fig. 33).
Fig. 30 FIRST PINION GEAR
1 - DIFFERENTIAL WINDOW
2 - PINION GEAR
3 - THRUST WASHER
Fig. 31 SECOND PINION GEAR
1 - DIFFERENTIAL WINDOW
2 - THRUST WASHER
3 - PINION GEAR
Fig. 32 SIDE GEARS
1 - SIDE GEAR
2 - SIDE GEAR
3 - PINION GEARS
Fig. 33 SIDE GEAR
1 - DIFFERENTIAL WINDOW
2 - SIDE GEAR
3 - 156 REAR AXLE - 11 1/2 AADR
DIFFERENTIAL (Continued)

(3) Install first pinion gear into the differential
window and side gears. Rotate the pinion gear to the
back of the case (Fig. 34).
(4) Install the other pinion gear and thrust
washer. Rotate the gears to align hole in the pinion
gears with hole in the differential case.
(5) Slide pinion shaft into the case and through
the pinion gears. Tap the shaft to seat the pinion
shaft snap-ring into the case (Fig. 35).
(6) Install ring gear.
INSTALLATION
(1) Clean the housing cavity with a flushing oil,
light engine oil or lint free cloth.
CAUTION: Do not use water, steam, kerosene or
gasoline for cleaning.
(2) Lubricate differential case bearing.
(3) Install differential case with bearings cups into
the housing.
NOTE: A light coat of grease on the cups will hold
them in place during installation.
(4) Install bearing caps and bolts (Fig. 36). Tighten
the bearing cap bolts finger-tight.
NOTE: Do not torque bearing cap and bolts at this
time.
Fig. 34 PINION GEAR
1 - DIFFERENTIAL WINDOW
2 - SIDE GEARS
3 - PINION GEAR
Fig. 35 PINION SHAFT INSTALLATION
1 - SNAP RING
2 - SIDE GEAR
3 - PINION GEAR
4 - PINION SHAFT
Fig. 36 CASE BEARING CAP
1 - DIFFERENTIAL HOUSING
2 - BEARING CAP
3 - ADJUSTER
DRREAR AXLE - 11 1/2 AA 3 - 157
DIFFERENTIAL (Continued)

(5) 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.
(6) Holding the differential case toward the pinion
gear, turn bearing adjusters with Spanner Wrench
8883 until they make contact with the differential
bearings/cups.
(7) Back off the ring gear side adjuster 4 holes, to
obtain initial ring gear backlash.
(8) Install ring gear side adjuster lock and bolt. Do
not tighten adjuster lock bolt at this time.
(9) Tighten pinion gear side adjuster firmly
against the differential case bearing cup.
(10) Rotate the pinion several times to seat the dif-
ferential bearings.
(11) Loosen pinion gear side adjuster until it is no
longer in contact with the bearing cup.
(12) Tighten pinion gear side adjuster until it just
makes contact with the bearing cup.
(13) Tighten pinion gear side adjuster an addi-
tional:
²New Bearings6 Adjuster Holes
²Original Bearings4 Adjuster Holes
(14) Install pinion gear side adjuster lock and bolt.
Do not tighten adjuster lock bolt at this time.
(15) Tighten bearing cap bolts to 281 N´m (207 ft.
lbs.).
(16) Tighten adjuster lock bolts to 25 N´m (18 ft.
lbs.) (Fig. 37).
(17) Measure ring gear backlash and check gear
tooth contact pattern. Refer to Adjustments for pro-
cedure.
(18) Install axle shaft gasket and install axle
shafts.
(19) Install differential housing gasket and cover.
Tighten cover bolts to 40 N´m (30 ft. lbs.).
(20) Fill axle with lubricant, refer to Lubrication &
Maintenance for capacity and lubricant type.
(21) Install fill plug and tighten to 32 N´m (24 ft.
lbs.).
DIFFERENTIAL TRAC-RITE
DESCRIPTION
The Trac-RiteŸ differential is a helical gear differ-
ential. The differential has two side gears, six pinion
gears and six pinion brake shoes.
NOTE: The differential is seviced as an assembly
only if damaged, but can be disassembled for
cleaning. The assembly should be cleaned every
time a bearing is changed due to damage.
OPERATION
When one wheel begins to spin the pinion gears on
that side are forced toward the pinion brake shoes.
The pinion brake shoes then cause frictional drag on
the opposite pinion gears and the side gear. These
friction forces transfer the power to the opposite
wheel. Once the frictional forces are overcome, differ-
entiation will occur. The torque will be continually
biased by the frictional forces to the high traction
wheel.
DISASSEMBLY
(1) Remove differential ring gear bolts.
(2) Remove differential case cover locating screws
(Fig. 38).
(3) Remove differential case cover.
(4) Remove side gear and thrust washer (Fig. 39).
NOTE: Mark all component locations.
Fig. 37 ADJUSTER LOCK BOLT
1 - DIFFERENTIAL CASE
2 - ADJUSTER LOCK
3 - ADJUSTER LOCK BOLT
4 - BEARING CAP BOLT
3 - 158 REAR AXLE - 11 1/2 AADR
DIFFERENTIAL (Continued)