Page 225 of 2627

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 components.
(5) Align propeller shaft and pinion companion
flange reference marks and tighten companion flange
bolts to 115 N´m (85 ft. lbs.).
(6) Install the wheels and tires.
(7) Fill differential to specifications.
(8) Remove lift from axle and lower the vehicle.
ADJUSTMENTS
Ring and pinion gears are supplied as matched
sets. Compensation for pinion depth variance is
achieved with a select shim, located between the rear
pinion bearing and pinion gear head.
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. 3).(1) Assemble Pinion Height Block 6739, Pinion
Block 8897 and rear pinion bearing onto Screw 6741
(Fig. 3).
(2) Insert assembled height gauge components,
rear bearing and screw into the housing through pin-
ion bearing cups (Fig. 4).
(3) Install front pinion bearing and Cone-nut 6740
onto the screw. Tighten cone-nut until Torque To
Rotate the screw is 1.7-2.26 N´m (15-20 in. lbs.) (Fig.
3).
(4) Place Arbor Discs 8289 on Arbor D-115-3 in
position in the housing side bearing cradles (Fig. 5).
(5) Install differential bearing caps on arbor discs
and snug the bearing cap bolts. Then cross tighten
cap bolts to 281 N´m (207 ft. lbs.).
NOTE: Arbor should rotate freely in the arbor discs.
(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. 6). Move the
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.
Fig. 3 PINION GEAR 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. 4 PINION HEIGHT BLOCK
1 - PINION BLOCK
2 - PINION HEIGHT BLOCK
3 - 144 REAR AXLE - 11 1/2 AADR
REAR AXLE - 11 1/2 AA (Continued)
Page 226 of 2627

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)
Page 227 of 2627

(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)
Page 228 of 2627
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 is set too low (Fig. 15). Increase pin-
ion gear height, by increasing the pinion depth shim
thickness.
²Pinion gear is set too high (Fig. 16). Decrease
pinion depth, by decreasing the pinion depth shim
thickness.
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
Fig. 16 HIGH PINION HEIGHT
DRREAR AXLE - 11 1/2 AA 3 - 147
REAR AXLE - 11 1/2 AA (Continued)
Page 229 of 2627
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)
Page 230 of 2627
DIAL INDICATOR STUD L-4438
SPLITTER 1130
PINION DEPTH GAUGE 6730
CUP INSTALLER 8153
ARBOR DISCS 8289
ADJUSTER WRENCH 8883
SEAL INSTALLER 8896
DRREAR AXLE - 11 1/2 AA 3 - 149
REAR AXLE - 11 1/2 AA (Continued)
Page 231 of 2627
PINION BLOCK 8897
SOCKET 8954
CUP INSTALLER 8960
CUP INSTALLER 8961
SEAL INSTALLER 8963
PLUG 8964
3 - 150 REAR AXLE - 11 1/2 AADR
REAR AXLE - 11 1/2 AA (Continued)
Page 232 of 2627
BEARING INSTALLER 8965
CUP INSTALLER 8968
PINION DRIVER 8977
FLANGE WRENCH 8979
PINION INSTALLER 8981
FLANGE PULLER 8992
DRREAR AXLE - 11 1/2 AA 3 - 151
REAR AXLE - 11 1/2 AA (Continued)