differential DODGE RAM 2002 Service Owner's Guide

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)

(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)

(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)

(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)

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)

SPECIFICATIONS
REAR AXLE - 248RBI
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.55, 4.10
Ring Gear Diameter 248 mm (9.75 in.)
Ring Gear Backlash 0.12-0.20 mm (0.005-0.008 in.)
Pinion Gear Standard Depth 127.0 mm (5.000 in.)
Pinion Bearing Preload - Original Bearings 1-2 N´m (10-20 in. lbs.)
Pinion Bearing Preload - New Bearings 2.3-5.1 N´m (20-45 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Fill Hole Plug 34 25 -
Differential Cover Bolts 41 30 -
Bearing Cap Bolts 108 80 -
Ring Gear Bolt 176 130 -
Pinion Nut 292-447 215-330 -
Axle Shaft Bolts 122-136 90-100 -
Hub Bearing Nut 163-190 120-140 -
SPECIAL TOOLS
REAR AXLE - 248RBI
Puller 6790
Wrench DD-1241-JD
Installer 5064
Installer D-111
BR/BEREAR AXLE - 248RBI 3 - 59
REAR AXLE - 248RBI (Continued)

CAUTION: Never loosen pinion gear nut to decrease
pinion rotating torque and never exceed specified pre-
load torque. If preload torque is exceeded a new pin-ion nut and collapsible spacer, if equipped, must be
installed.
(8) If rotating torque is low, use Yoke Holder 6719
to hold the pinion yoke (Fig. 25) and tighten the pin-
ion shaft nut in 6.8 N´m (5 ft. lbs.) increments until
proper rotating torque is achieved.
NOTE: The bearing rotating torque should be con-
stant during a complete revolution of the pinion. If
the rotating torque varies, this indicates a binding
condition.
(9) Install propeller shaft with reference marks
aligned.
(10) Add gear lubricant to the differential housing,
if necessary.
(11) Install wheel and tire assemblies and lower
the vehicle.
(12)
Pump the brake pedal before moving the vehicle.
DIFFERENTIAL
REMOVAL
(1) Raise and support the vehicle.
(2) Remove fill hole plug from the differential
housing cover.
(3) Remove differential housing cover and drain
lubricant from the housing.
(4) Clean the housing cavity with a flushing oil,
light engine oil or lint free cloth.Do not use water,
steam, kerosene or gasoline for cleaning.
(5) Remove axle shafts.
(6) Note the orientation of the installation refer-
ence letters stamped on the bearing caps and hous-
ing machined sealing surface (Fig. 27).
Fig. 25 TIGHTEN PINION NUT
1 - DIFFERENTIAL HOUSING
2 - YOKE HOLDER
3 - TORQUE WRENCH
Fig. 26 PINION ROTATING TORQUE
1 -TORQUE WRENCH
2 - PINION YOKE
Fig. 27 BEARING CAP IDENTIFICATION
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
3 - 64 REAR AXLE - 248RBIBR/BE
PINION SEAL (Continued)

(7) Remove the differential bearing caps.
(8) Position Spreader W-129-B with the tool dowel
pins seated in the locating holes (Fig. 28).
(9) Install the hold down clamps and tighten the
tool turnbuckle finger-tight.
(10) Install a Pilot Stud C-3288-B at the left side
of the differential housing. Attach dial indicator to
housing pilot stud. Load the indicator plunger
against the opposite side of the housing (Fig. 28) and
zero the indicator.
(11) Spread the housing enough to remove the case
from the housing. Measure the distance with the dial
indicator (Fig. 28).
CAUTION: Never spread the housing over 0.50 mm
(0.020 in). If housing is over-spread, it could be dis-
torted or damaged.
(12) Remove the dial indicator.
(13) Pry the differential case loose from the hous-
ing. To prevent damage, pivot on housing with the
end of the pry bar against spreader (Fig. 29).
(14) Remove the case from housing. Tag bearing
cups to indicate their location.
DISASSEMBLY
(1) Remove roll-pin holding mate shaft in housing.
(2) Remove pinion gear mate shaft (Fig. 30).
(3) Rotate the differential side gears and remove
the pinion mate gears and thrust washers (Fig. 31).
Fig. 28 SPREAD DIFFERENTIAL HOUSING
1 - SPREADER
2 - DIAL INDICATOR
3 - DIFFERENTIAL
4 - DIFFERENTIAL HOUSING
5 - PILOT STUD
Fig. 29 DIFFERENTIAL REMOVAL
1 - DIFFERENTIAL
2-PRYBAR
Fig. 30 PINION MATE SHAFT
1 - PINION MATE GEAR
2 - PINION MATE SHAFT
3 - SIDE GEAR
4 - DRIFT
BR/BEREAR AXLE - 248RBI 3 - 65
DIFFERENTIAL (Continued)

(4) Remove the differential side gears and thrust
washers.
ASSEMBLY
(1) Install the differential side gears and thrust
washers.
(2) Install the pinion mate gears and thrust wash-
ers.
(3) Install the pinion gear mate shaft.
(4) Align the hole in the pinion gear mate shaft
with the hole in the differential case.
(5) Install and seat the pinion mate shaft roll-pin
in the differential case and mate shaft with a punch
and hammer (Fig. 32). Peen the edge of the roll-pin
hole in the differential case slightly in two places,
180É apart.
(6) Lubricate all differential components with
hypoid gear lubricant.
INSTALLATION
NOTE: If replacement differential bearings or differ-
ential case are being installed, differential side
bearing shim requirements may change. Refer to
Adjustments (Differential Bearing Preload and Gear
Backlash) procedures to determine proper shim
selection.(1) Position Spreader W-129-B with the tool dowel
pins seated in the locating holes. Install the hold
down clamps and tighten the tool turnbuckle finger-
tight.
(2) Install a Pilot Stud C-3288-B at the left side of
the differential housing and attach dial indicator to
the pilot stud. Load the indicator plunger against the
opposite side of the housing and zero the dial indica-
tor.
(3) Spread the housing enough to install the case
in the housing. Measure the distance with the dial
indicator.
CAUTION: Never spread the housing over 0.50 mm
(0.020 in). If housing is over-spread, it could be dis-
torted or damaged.
(4) Remove the dial indicator.
(5) Install differential into the housing. Tap the
differential case with a rawhide/rubber hammer to
ensure the bearings are seated in housing (Fig. 33).
(6) Remove the spreader.
(7) Install bearing caps in their original locations
(Fig. 34) and tighten bearing cap bolts in a criss-
cross pattern to 109 N´m (80 ft. lbs.).
(8) Install axle shafts.
(9) Install the hub bearings.
(10) Apply a bead of red Mopar Silicone Rubber
Sealant or equivalent to the housing cover (Fig. 35).
Fig. 31 PINION MATE/SIDE GEAR
1 - THRUST WASHER
2 - SIDE GEAR
3 - PINION MATE GEARFig. 32 PINION MATE SHAFT ROLL-PIN
1 - PUNCH
2 - PINION MATE SHAFT
3 - MATE SHAFT LOCKPIN
3 - 66 REAR AXLE - 248RBIBR/BE
DIFFERENTIAL (Continued)

CAUTION: If housing cover is not installed within 3
to 5 minutes, the cover must be cleaned and new
RTV applied or adhesion quality will be compro-
mised.
(11) Install the cover and tighten bolts in a criss-
cross pattern to 47 N´m (35 ft. lbs.).
(12) Fill the differential with Mopar Hypoid Gear
Lubricant or equivalent to bottom of the fill plug
hole.(13) Install fill hole plug and tighten to 34 N´m (25
ft. lbs.).
(14) Remove support and lower vehicle.
DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING - TRAC-LOKT
The most common problem is a chatter noise when
turning corners. Before removing the unit for repair,
drain, flush and refill the axle with the specified
lubricant. A container of Mopar Trac-loktLubricant
(friction modifier) should be added after repair ser-
vice or during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
DIFFERENTIAL TEST
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
Fig. 33 DIFFERENTIAL CASE
1 - RAWHIDE HAMMER
Fig. 34 Bearing Cap Reference
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
Fig. 35 DIFFERENTIAL COVER - TYPICAL
1 - SEALANT SURFACE
2 - SEALANT
3 - SEALANT THICKNESS
BR/BEREAR AXLE - 248RBI 3 - 67
DIFFERENTIAL (Continued)