1998 DODGE RAM 1500 bolt pattern

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 - 10 1/2 AA 3 - 117
REAR AXLE - 10 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 the backlash, by moving the ring closer
to the pinion gear using the adjusters.
²Ring gear too close to pinion gear (Fig. 12).
Increase the 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 - 118 REAR AXLE - 10 1/2 AADR
REAR AXLE - 10 1/2 AA (Continued)

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.
(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 165 N´m (122 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 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.).
Fig. 36 CASE BEARING CAP
1 - DIFFERENTIAL HOUSING
2 - BEARING CAP
3 - ADJUSTERFig. 37 ADJUSTER LOCK BOLT
1 - DIFFERENTIAL CASE
2 - ADJUSTER LOCK
3 - ADJUSTER LOCK BOLT
4 - BEARING CAP BOLT
3 - 130 REAR AXLE - 10 1/2 AADR
DIFFERENTIAL (Continued)

(13) Rotate pinion several times to seat bearings.
(14) Measure pinion rotating torque with an inch
pound torque wrench (Fig. 63). Tighten pinion nut in
small increments until pinion rotating torque is:
²New Pinion Bearings:1.7-2.8 N´m (15-25 in.
lbs.)
²Original Pinion Bearings:1.1-2.2 N´m (10-20
in. lbs.)
(15) Rotate pinion several times then verify pinion
rotating torque again.
(16) Position the ring gear on differential case and
start twonewring gear bolts.
(17) Install the rest of thenewring gear bolts and
tighten them alternately to seat the ring gear.
(18) Torque ring gear bolts to 237 N´m (175 ft.
lbs.).
(19) If exciter ring was removed, position differen-
tial assembly on differential Plug 8888 (Fig. 64) and
place exciter ring on the differential case.
(20) Install the exciter ring on the differential case
evenly with a hammer and brass punch (Fig. 65).
Drive the ring down until it is seated against the
ring gear.
CAUTION: Do not damage exciter ring teeth during
installation.
(21) Install differential into the housing.
(22) Verify ring gear backlash and gear contact
pattern.
(23) Measure final rotating torque with an inch
pound torque wrench. The final pinion rotating
torque plus differential case bearing preload is:
²New Bearings:3.4-5.6 N´m (30-50 in. lbs.)²Original Bearings:2.8-5.1 N´m (25-45 in. lbs.)
(24) Install axle shafts.
(25) Install the propeller shaft with the reference
marks aligned.
(26) Install differential cover with gasket and
tighten bolts to 40 N´m (30 ft. lbs.).
(27) Fill differential with fluid and tighten fill plug
to 32 N´m (24 ft. lbs.).
Fig. 63 PINION ROTATING TORQUE
1 - PINION FLANGE
2 - TORQUE WRENCH
Fig. 64 EXCITER RING
1 - EXCITER RING
2 - RING GEAR
3 - DIFFERENTIAL PLUG
4 - DIFFERENTIAL CASE
Fig. 65 EXCITER RING INSTALLATION
1 - EXCITER RING
2 - PUNSH
3 - RING GEAR
DRREAR AXLE - 10 1/2 AA 3 - 139
PINION GEAR/RING GEAR/TONE RING (Continued)

Condition Possible Causes Correction
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 lifting device under axle and secure
lift to the axle.
(3) Remove wheels and tires assemblies.
(4) Remove all brake components.
(5) Mark propeller shaft and companion flange for
installation alignment reference.
(6) Remove propeller shaft.
(7) Remove shock absorbers from axle (Fig. 1).
(8) Remove U-bolts from axle (Fig. 2).(9) Remove axle from the vehicle.
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
DRREAR AXLE - 11 1/2 AA 3 - 143
REAR AXLE - 11 1/2 AA (Continued)

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)

(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)