2002 DODGE RAM differential

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. 5).
(1) Assemble Pinion Height Block 6739, Pinion
Block 6736 and rear pinion bearing onto Screw 6741
(Fig. 5).
(2) Insert assembled height gauge components,
rear bearing and screw into the housing through pin-
ion bearing cups (Fig. 6).
(3) Install front pinion bearing and Cone-nut 6740
hand tight (Fig. 5).
(4) Place Arbor Disc 6732 on Arbor D-115-3 in posi-
tion in the housing side bearing cradles (Fig. 7).
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. 8). Move the
scooter block till dial indicator crests the arbor, then
record the highest reading.
(9) Select a shim/slinger equal to the dial indicator
reading plus the pinion depth variance number
etched in the face of the pinion (Fig. 3). For example,
if the depth variance is ±2, add +0.002 in. to the dial
indicator reading.
Fig. 5 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. 6 PINION HEIGHT BLOCK
1 - PINION BLOCK
2 - PINION HEIGHT BLOCK
Fig. 7 GAUGE TOOLS IN HOUSING
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
BR/BEFRONT AXLE - 248FBI 3 - 21
FRONT AXLE - 248FBI (Continued)

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 shim
thickness 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. 9). 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.
(5) Install differential case in the housing.
(6) Install the marked bearing caps in their correct
positions and snug the bolts (Fig. 10).
Fig. 8 PINION GEAR DEPTH MEASUREMENT
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
Fig. 9 SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM/SLINGER
2 - DIFFERENTIAL BEARING SHIM
Fig. 10 BEARING CAP BOLTS
1 - BEARING CAP
2 - DIFFERENTIAL HOUSING
3 - DIFFERENTIAL CASE
3 - 22 FRONT AXLE - 248FBIBR/BE
FRONT AXLE - 248FBI (Continued)

(7) Using a dead-blow hammer, seat the differen-
tial dummy bearings to each side of the housing (Fig.
11) and (Fig. 12).
(8) Thread Pilot Stud C-3288-B into rear cover bolt
hole below ring gear (Fig. 13).
(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. 13).
(10) Push and hold differential case to pinion gear
side of the housing and zero dial indicator (Fig. 14).
Fig. 11 SEAT PINION GEAR SIDE DUMMY BEARING
1 - DEAD-BLOW HAMMER
2 - DIFFERENTIAL HOUSING
3 - DIFFERENTIAL CASE
Fig. 12 SEAT RING GEAR SIDE DUMMY BEARING
1 - DIFFERENTIAL HOUSING
2 - DEAD-BLOW HAMMER
3 - DIFFERENTIAL CASE
Fig. 13 DIFFERENTIAL SIDE PLAY
1 - DIFFERENTIAL CASE
2 - DIFFERENTIAL HOUSING
3 - PILOT STUD
4 - DIAL INDICATOR
Fig. 14 DIAL INDICATOR LOCATION
1 - DIFFERENTIAL CASE TO PINION GEAR SIDE
2 - PILOT STUD
3 - DIAL INDICATOR ARM
4 - DIAL INDICATOR FACE
BR/BEFRONT AXLE - 248FBI 3 - 23
FRONT AXLE - 248FBI (Continued)

(11) Push and hold differential case to ring gear
side of the housing and record the dial indicator
reading (Fig. 15).
(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.
(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. 12).
(18) Position dial indicator plunger on a flat sur-
face between the ring gear bolt heads (Fig. 13).
(19) Push and hold differential case toward pinion
gear and zero the dial indicator (Fig. 16).
(20) Push and hold differential case to ring gear
side of the housing and record dial indicator reading
(Fig. 17). This is the shim thickness needed on the
ring gear side of the differential case for proper back-
lash.
(21) 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.
(22) Rotate dial indicator out of the way on pilot
stud.
(23) Remove differential case and dummy bearings
from the housing.(24) Install selected side bearing shims onto the
differential case hubs.
(25) Install side bearings on differential case hubs
with Install C-4487-1 and Handle C-4171.
(26) Install bearing cups on differential.
(27) Install Spreader W-129-B and some items
from Adapter Set 6987 on the housing and spread
open enough to receive differential case.
Fig. 15 DIFFERENTIAL CASE RING GEAR SIDE
1 - DIAL INDICATOR
2 - DIFFERENTIAL CASE TO RING GEAR SIDE
3 - DIFFERENTIAL HOUSING
Fig. 16 DIFFERENTIAL CASE PINION GEAR SIDE
1 - DIAL INDICATOR FACE
2 - DIFFERENTIAL CASE TO PINION GEAR SIDE
3 - PINION GEAR
4 - DIFFERENTIAL HOUSING
5 - DIFFERENTIAL CASE
Fig. 17 DIFFERENTIAL CASE RING GEAR SIDE
1 - DIAL INDICATOR
2 - DIFFERENTIAL CASE TO RING GEAR SIDE
3 - PINION GEAR
4 - DIFFERENTIAL HOUSING
5 - DIFFERENTIAL CASE
3 - 24 FRONT AXLE - 248FBIBR/BE
FRONT AXLE - 248FBI (Continued)

CAUTION: Never spread housing over 0.50 mm
(0.020 in.). The housing can be damaged if over-
spread.
(28) Install differential case into the housing.
(29) Remove spreader from the housing.
(30) Rotate differential case several times to seat
the side bearings.
(31) Position indicator plunger against a ring gear
tooth (Fig. 18).
(32) Push and hold ring gear upward while not
allowing the pinion gear to rotate.
(33) Zero dial indicator face to pointer.
(34) 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.
19).
(35) 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.
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.
20)and adjust pinion depth and gear backlash as nec-
essary.
Fig. 18 RING GEAR BACKLASH
1 - DIAL INDICATOR
Fig. 19 BACKLASH SHIM
BR/BEFRONT AXLE - 248FBI 3 - 25
FRONT AXLE - 248FBI (Continued)

SPECIFICATIONS
FRONT AXLE - 248FBI
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.54, 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 mm (5.000 in.)
Pinion Bearing Preload - Original Bearing 1-2 N´m (10-20 in. lbs.)
Pinion Bearing Preload - New Bearing 2.26-4.52 N´m (20-40 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 Bolts 176 130 -
Pinion Nut 292-678 215-496 -
Axle Nut 237 175 -
Shift Motor Bolts 11 8 96
SPECIAL TOOLS
FRONT AXLE
REMOVER - C-452
SPREADER - W-129-B
INSTALLER, BEARING - C-3095-A
WRENCH, FLANGE - C-3281
BR/BEFRONT AXLE - 248FBI 3 - 27
FRONT AXLE - 248FBI (Continued)

AXLE SHAFTS
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assembly.
(3) Remove brake caliper, rotor and ABS wheel
speed sensor if equipped. Refer to 5 Brakes for pro-
cedures.
(4) Remove the cotter pin and axle hub nut.
(5) Remove hub bearing bolts (Fig. 21) and remove
hub bearing from the steering knuckle.
(6) Remove brake dust shield from knuckle.
(7) Remove axle shaft from the housing. Avoid
damaging the axle shaft oil seal.
INSTALLATION
(1) Clean axle shaft and apply a thin film of
Mopar Wheel Bearing Grease to the shaft splines,
seal contact surface, hub bore.
(2) Install axle shaft into the housing and differen-
tial side gears. Avoid damaging axle shaft oil seals in
the differential.
(3) Install dust shield and hub bearing on knuckle.
(4) Install hub bearing bolts and tighten to 170
N´m (125 ft. lbs.).
(5) Install axle washer and nut, tighten nut to 237
N´m (175 ft. lbs.). Align nut to next cotter pin hole
and install new cotter pin.
(6) Install ABS wheel speed sensor, brake rotor
and caliper. Refer to Brakes for proper procedures.
(7) Install wheel and tire assembly.
(8) Remove support and lower the vehicle.
BLOCK, ADAPTER ± C-239-37
BLOCK, ADAPTER ± C-239-62
HOLDER, YOKE - 6719A
PINION DEPTH, SET ± 6730
Fig. 21 HUB AND KNUCKLE
1 - KNUCKLE
2 - HUB BEARING
BR/BEFRONT AXLE - 248FBI 3 - 29
FRONT AXLE - 248FBI (Continued)

AXLE SHAFT SEALS
REMOVAL
(1) Remove hub bearings and axle shafts.
(2) Remove axle shaft seal from the differential
housing with a long drift or punch.Be careful not
to damage housing.
(3) Clean the inside perimeter of the differential
housing with fine crocus cloth.
INSTALLATION
(1) Apply a light film of oil to the inside lip of the
new axle shaft seal.
(2) Install the inner axle seal (Fig. 25).
(3) Install axles and hub bearings.
AXLE VACUUM MOTOR
DESCRIPTION
The disconnect axle control system consists of:
²Shift motor.
²Indicator switch.
²Vacuum switch.
²Vacuum harness (Fig. 26).
OPERATION
The shift motor receives a vacuum signal from the
switch mounted on the transfer case when the vehi-
cle operator wants to switch from two wheel drive
mode to four wheel drive mode, or vice versa. When
this signal is received, the shift motor begins to move
the shift fork and collar within the axle housing. In
the four wheel drive mode, the shift collar connects
the axle intermediate shaft to the axle shaft to sup-
ply engine power to both front wheels. In two wheel
drive mode, the shift collar is disengaged from the
intermediate shaft and the intermediate shaft is
allowed to free-spin. When the two shafts are disen-
gaged, the load on the engine is reduced, thereby pro-
viding better fuel economy and road handling.
Fig. 25 SEAL INSTALLATION
1 - DIFFERENTIAL HOUSING
2 - POSITION FOR OPEN-END WRENCH
3 - SPECIAL TOOL 5041-2
4 - SPECIAL TOOL 8417
5 - SEAL
6 - SPECIAL TOOL 8411
Fig. 26 VACUUM CONTROL SYSTEM
1 - CHECK VALVE
2 - CONTROL SWITCH ON TRANSFER CASE
3 - AIR VENT FILTER
4 - AXLE SHIFT MOTOR
5 - INDICATOR SWITCH
BR/BEFRONT AXLE - 248FBI 3 - 31