Page 105 of 2255

Condition Possible Causes Correction
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.
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.
3 - 50 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)
Page 106 of 2255

REMOVAL
(1) Raise and support the vehicle.
(2) Position an axle lift under the axle and secure
it to the axle.
(3) Remove the wheels and tires.
(4) Remove RWAL sensor from the differential
housing, if necessary.
(5) Remove brake hose from the axle junction
block.
(6) Disconnect parking brake cables and cable
brackets.
(7) Remove vent hose from the axle shaft tube.
(8) Mark propeller shaft and yoke for installation
alignment reference.
(9) Remove propeller shaft.
(10) Remove shock absorbers from the axle brack-
ets.
(11) Remove spring clamps and spring brackets.
(12) Remove axle from the vehicle.
INSTALLATION
(1) Raise axle with lift and align to the leaf spring
centering bolts.
(2) Install spring clamps and spring brackets.
(3) Install shock absorbers and tighten to specifica-
tions.
(4) Install RWAL sensor to the differential hous-
ing, if necessary.
(5) Install parking brake cables and cable brackets
(6) Install brake hose to the axle junction block.
(7) Install axle vent hose.
(8) Install propeller shaft with reference marks
aligned.
(9) Install wheels and tires assemblies.
(10) Add gear lubricant, if necessary.
(11) Remove lift from the axle and lower the vehi-
cle.
ADJUSTMENTS
Ring and pinion gears are supplied as matched
sets only. The identifying numbers for the ring and
pinion gear are etched into the face of each gear (Fig.
4). A plus (+) number, minus (±) number or zero (0) is
etched into the face of the pinion gear. This number
is the amount (in thousandths of an inch) the depth
varies from the standard depth setting of a pinion
etched with a (0). The standard setting from the cen-
ter line of the ring gear to the back face of the pinion
is 127 mm (5.00 in.). The standard depth provides
the best gear tooth contact pattern. Refer to Back-
lash and Contact Pattern in this section for addi-
tional information.
Compensation for pinion depth variance is
achieved with a select shim. The shims are placed
between the rear pinion bearing and the pinion gear
head (Fig. 5).If a new gear set is being installed, note the depth
variance etched into both the original and replace-
ment pinion. Add or subtract this number from the
thickness of the original depth shim/oil slinger to
compensate for the difference in the depth variances.
Refer to the Depth Variance chart.
Note where Old and New Pinion Marking columns
intersect. Intersecting figure represents plus or
minus the amount needed.
Fig. 4 PINION GEAR ID NUMBERS
1 - PRODUCTION NUMBERS
2 - PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER
Fig. 5 SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM
2 - DIFFERENTIAL BEARING SHIM
BR/BEREAR AXLE - 248RBI 3 - 51
REAR AXLE - 248RBI (Continued)
Page 107 of 2255

Note the etched number on the face of the pinion
gear head (±1, ±2, 0, +1, +2, etc.). The numbers rep-
resent thousands of an inch deviation from the stan-
dard. If the number is negative, add that value to therequired thickness of the depth shims. If the number
is positive, subtract that value from the thickness of
the depth shim. If the number is 0 no change is nec-
essary.
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 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. 6).
(1) Assemble Pinion Height Block 6739, Pinion
Block 6736 and rear pinion bearing onto Screw 6741
(Fig. 6).
(2) Insert assembled height gauge components,
rear bearing and screw into the housing through pin-
ion bearing cups (Fig. 7).
(3) Install front pinion bearing and Cone-nut 6740
hand tight (Fig. 6).
(4) Place Arbor Disc 6732 on Arbor D-115-3 in posi-
tion in the housing side bearing cradles (Fig. 8).
NOTE: Arbor Discs 6732 has different step diame-
ters to fit other axles. Choose proper step for axle
being serviced.
(5) Install differential bearing caps on arbor discs
and snug the bearing cap bolts. Then cross tighten
cap bolts to 108 N´m (80 ft. lbs.).
(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. 9). Move the
Fig. 6 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
3 - 52 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)
Page 108 of 2255

scooter block till dial indicator crests the arbor, then
record the highest reading.
(9) Select a shim equal to the dial indicator read-
ing plus the pinion depth variance number etched in
the face of the pinion (Fig. 4). For example, if the
depth variance is ±2, add +0.002 in. to the dial indi-
cator reading.
DIFFERENTIAL SIDE BEARING PRELOAD AND
GEAR BACKLASH
Differential side bearing preload and gear backlash
is achieved by selective shims positioned behind the
differential side bearing cones. The proper shimthickness can be determined using slip-fit Dummy
Bearings D-343 in place of the differential side bear-
ings and a Dial Indicator C-3339. Before proceeding
with the differential bearing preload and gear back-
lash measurements, measure the pinion gear depth
and prepare the pinion for installation. Establishing
proper pinion gear depth is essential to establishing
gear backlash and tooth contact patterns. After the
overall shim thickness to take up differential side
play is measured, the pinion is installed, and the
gear backlash shim thickness is measured. The over-
all shim thickness is the total of the dial indicator
reading and the preload specification added together.
The gear backlash measurement determines the
thickness of the shim used on the ring gear side of
the differential case. Subtract the gear backlash shim
thickness from the total overall shim thickness and
select that amount for the pinion gear side of the dif-
ferential (Fig. 10). Differential shim measurements
are performed with spreader W-129-B removed.
SHIM SELECTION
NOTE: It is difficult to salvage the differential side
bearings during the removal procedure. Install
replacement bearings if necessary.
(1) Remove differential side bearings from differ-
ential case.
(2) Remove factory installed shims from differen-
tial case.
(3) Install ring gear on differential case and
tighten bolts to specification.
(4) Install dummy side bearings D-343 on differen-
tial case.
Fig. 7 PINION HEIGHT BLOCK
1 - PINION BLOCK
2 - PINION HEIGHT BLOCK
Fig. 8 GAUGE TOOLS IN HOUSING
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
Fig. 9 PINION DEPTH MEASUREMENT
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
BR/BEREAR AXLE - 248RBI 3 - 53
REAR AXLE - 248RBI (Continued)
Page 109 of 2255

(5) Install differential case in the housing.
(6) Install the marked bearing caps in their correct
positions and snug the bolts (Fig. 11).
(7) Using a dead-blow hammer, seat the differen-
tial dummy bearings to each side of the housing (Fig.
12) and (Fig. 13).
(8) Thread Pilot Stud C-3288-B into rear cover bolt
hole below ring gear (Fig. 14).(9) Attach the Dial Indicator C-3339 to pilot stud.
Position the dial indicator plunger on a flat surface
between the ring gear bolt heads (Fig. 14).
(10) Push and hold differential case to pinion gear
side of the housing and zero dial indicator (Fig. 15).
(11) Push and hold differential case to ring gear
side of the housing and record the dial indicator
reading (Fig. 16).
(12) Add 0.38 mm (0.015 in.) to the zero end play
total. This total represents the thickness of shims
needed to preload the new bearings when the differ-
ential is installed.
Fig. 10 SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM
2 - DIFFERENTIAL BEARING SHIM
Fig. 11 BEARING CAP BOLTS
1 - BEARING CAP
2 - DIFFERENTIAL HOUSING
3 - DIFFERENTIAL CASE
Fig. 12 SEAT PINION GEAR SIDE DUMMY BEARING
1 - DEAD-BLOW HAMMER
2 - DIFFERENTIAL HOUSING
3 - DIFFERENTIAL CASE
Fig. 13 SEAT RING GEAR SIDE DIFFERENTIAL
DUMMY BEARING
1 - DIFFERENTIAL HOUSING
2 - DEAD-BLOW HAMMER
3 - DIFFERENTIAL CASE
3 - 54 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)
Page 110 of 2255

(13) Rotate dial indicator out of the way on the
pilot stud.
(14) Remove differential case and dummy bearings
from the housing.(15) Install the pinion gear in the housing. Install
the pinion yoke and establish the correct pinion
rotating torque.
(16) Install differential case and dummy bearings
D-343 in the housing (without shims), install bearing
caps and tighten bolts snug.
(17) Seat ring gear side dummy bearing (Fig. 13).
(18) Position the dial indicator plunger on a flat
surface between the ring gear bolt heads (Fig. 14).
(19) Push and hold differential case toward pinion
gear and zero the dial indicator (Fig. 17).
Fig. 14 DIFFERENTIAL SIDE PLAY MEASUREMENT
1 - DIFFERENTIAL CASE
2 - DIFFERENTIAL HOUSING
3 - PILOT STUD
4 - DIAL INDICATOR
Fig. 15 DIAL INDICATOR LOCATION
1 - DIFFERENTIAL CASE TO PINION GEAR SIDE
2 - PILOT STUD
3 - DIAL INDICATOR ARM
4 - DIAL INDICATOR FACE
Fig. 16 DIFFERENTIAL CASE TO RING GEAR SIDE
1 - DIAL INDICATOR
2 - DIFFERENTIAL CASE TO RING GEAR SIDE
3 - DIFFERENTIAL HOUSING
Fig. 17 DIFFERENTIAL CASE TO PINION GEAR
SIDE
1 - DIAL INDICATOR FACE
2 - DIFFERENTIAL CASE TO PINION GEAR SIDE
3 - PINION GEAR
4 - DIFFERENTIAL HOUSING
5 - DIFFERENTIAL CASE
BR/BEREAR AXLE - 248RBI 3 - 55
REAR AXLE - 248RBI (Continued)
Page 111 of 2255

(20) Push and hold differential case to ring gear
side of the housing and record dial indicator reading
(Fig. 18).
(21) This is the shim thickness needed on the ring
gear side of the differential case for proper backlash.
(22) Subtract the backlash shim thickness from
the total preload shim thickness. The remainder is
the shim thickness required on the pinion side of the
housing.
(23) Rotate dial indicator out of the way on pilot
stud.
(24) Remove differential case and dummy bearings
from the housing.
(25) Install the selected side bearing shims onto
the differential case hubs.
(26) Install side bearings on differential case hubs
with Install C-4487-1 and Handle C-4171.
(27) Install bearing cups on differential.
(28) Install Spreader W-129-B and some items
from Adapter Set 6987 on the housing and spread
open enough to receive differential case.CAUTION: Never spread housing over 0.50 mm
(0.020 in.). The housing can be damaged if over-
spread.
(29) Install differential case into the housing.
(30) Remove spreader from the housing.
(31) Rotate the differential case several times to
seat the side bearings.
(32) Position the indicator plunger against a ring
gear tooth (Fig. 19).
(33) Push and hold ring gear upward while not
allowing the pinion gear to rotate.
(34) Zero dial indicator face to pointer.
(35) Push and hold ring gear downward while not
allowing the pinion gear to rotate. Dial indicator
reading should be between 0.12 mm (0.005 in.) and
0.20 mm (0.008 in.). If backlash is not within specifi-
cations transfer the necessary amount of shim thick-
ness from one side of the housing to the other (Fig.
20).
(36) Verify differential case and ring gear runout
by measuring ring to pinion gear backlash at eight
locations around the ring gear. Readings should not
vary more than 0.05 mm (0.002 in.). If readings vary
more than specified, the ring gear or the differential
case is defective.
After the proper backlash is achieved, perform
Gear Contact Pattern Analysis procedure.
Fig. 18 DIFFERENTIAL CASE TO RING GEAR SIDE
1 - DIAL INDICATOR
2 - DIFFERENTIAL CASE TO RING GEAR SIDE
3 - PINION GEAR
4 - DIFFERENTIAL HOUSING
5 - DIFFERENTIAL CASE
Fig. 19 RING GEAR BACKLASH MEASUREMENT
1 - DIAL INDICATOR
3 - 56 REAR AXLE - 248RBIBR/BE
REAR AXLE - 248RBI (Continued)
Page 112 of 2255

GEAR CONTACT PATTERN
The ring and pinion gear contact patterns will
show if the pinion depth is correct. It will also show
if the ring gear backlash has been adjusted correctly.
The backlash can be adjusted within specifications to
achieve desired tooth contact patterns.
(1) Apply a thin coat of hydrated ferric oxide or
equivalent to the drive and coast side of the ring gear
teeth.
(2) Wrap, twist and hold a shop towel around the
pinion yoke to increase the turning resistance of the
pinion. This will provide a more distinct contact pat-
tern.
(3) With a boxed end wrench on the ring gear bolt,
rotate the differential case one complete revolution in
both directions while a load is being applied from
shop towel.
The areas on the ring gear teeth with the greatest
degree of contact against the pinion teeth will squee-
gee the compound to the areas with the least amount
of contact. Note and compare patterns on the ring
gear teeth to Gear Tooth Contact Patterns chart (Fig.
21)and adjust pinion depth and gear backlash as nec-
essary.
Fig. 20 BACKLASH SHIM
BR/BEREAR AXLE - 248RBI 3 - 57
REAR AXLE - 248RBI (Continued)