DODGE RAM 2002 Service Manual PDF

LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).
²Worn or out of balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear end
vibration. Do not overlook engine accessories, brack-
ets and drive belts.All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged) can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
DIAGNOSTIC CHART
Condition Possible Causes Correction
Wheel Noise 1. Wheel loose. 1. Tighten loose nuts.
2. Faulty, brinelled wheel bearing. 2. Replace bearing.
Axle Shaft Noise 1. Misaligned axle tube. 1. Inspect axle tube alignment.
Correct as necessary.
2. Bent or sprung axle shaft. 2. Inspect and correct as necessary.
3. End-play in pinion bearings. 3. Refer to pinion pre-load
information and correct as
necessary.
4. Excessive gear backlash
between the ring gear and pinion.4. Check adjustment of the ring
gear and pinion backlash. Correct
as necessary.
5. Improper adjustment of pinion
gear bearings.5. Adjust the pinion bearings
pre-load.
6. Loose pinion yoke nut. 6. Tighten the pinion yoke nut.
7. Scuffed gear tooth contact
surfaces.7. Inspect and replace as
necessary.
3 - 16 FRONT AXLE - 248FBIBR/BE
FRONT AXLE - 248FBI (Continued)

Condition Possible Causes Correction
Axle Shaft Broke 1. Misaligned axle tube. 1. Replace the broken shaft after
correcting tube mis-alignment.
2 Vehicle overloaded. 2. Replace broken shaft and avoid
excessive weight on vehicle.
3. Erratic clutch operation. 3. Replace broken shaft and avoid
or correct erratic clutch operation.
4. Grabbing clutch. 4. Replace broken shaft and inspect
and repair clutch as necessary.
Differential Cracked 1. Improper adjustment of the
differential bearings.1. Replace case and inspect gears
and bearings for further damage.
Set differential bearing pre-load
properly.
2. Excessive ring gear backlash. 2. Replace case and inspect gears
and bearings for further damage.
Set ring gear backlash properly.
3. Vehicle overloaded. 3. Replace case and inspect gears
and bearings for further damage.
Avoid excessive vehicle weight.
4. Erratic clutch operation. 4. Replace case and inspect gears
and bearings for further damage.
Avoid erratic use of clutch.
Differential Gears Scored 1. Insufficient lubrication. 1. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
2. Improper grade of lubricant. 2. Replace scored gears. Fill
differential with the correct fluid type
and quantity.
3. Excessive spinning of one
wheel/tire.3. Replace scored gears. Inspect all
gears, pinion bores, and shaft for
damage. Service as necessary.
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.
BR/BEFRONT AXLE - 248FBI 3 - 17
FRONT AXLE - 248FBI (Continued)

Condition Possible Causes Correction
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.
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) Remove wheels and tires.
(3) Remove brake calipers and rotors. Refer to 5
Brakes for procedures.
(4) Remove ABS wheel speed sensors, if equipped.
Refer to 5 Brakes for procedures.
(5) Disconnect axle vent hose.
(6) Disconnect vacuum hose and electrical connec-
tor at disconnect housing.
(7) Remove front propeller shaft.
(8) Disconnect stabilizer bar links at the axle
brackets.
(9) Disconnect shock absorbers from axle brackets.
(10) Disconnect track bar from the axle bracket.
(11) Disconnect tie rod and drag link from the
steering knuckles.
(12) Position suitable lifting device under the axle
assembly.(13) Secure axle to lifting device.
(14) Mark suspension alignment cams for installa-
tion reference.
(15) Disconnect upper and lower suspension arms
from the axle bracket.
(16) Lower the axle. The coil springs will drop
with the axle.
(17) Remove the coil springs from the axle bracket.
INSTALLATION
CAUTION: Suspension components with rubber
bushings should be tightened with the weight of the
vehicle on the suspension, at normal height. If
springs are not at their normal ride position, vehicle
ride comfort could be affected and premature bush-
ing wear may occur. Rubber bushings must never
be lubricated.
(1) Support the axle on a suitable lifting device.
3 - 18 FRONT AXLE - 248FBIBR/BE
FRONT AXLE - 248FBI (Continued)

(2) Secure axle to lifting device.
(3) Position the axle under the vehicle.
(4) Install springs, retainer clip and bolts.
(5) Raise axle and align it with the spring pads.
(6) Position upper and lower suspension arms in
the axle brackets. Install bolts, nuts and align the
suspension alignment cams to the reference marks.
Do not tighten at this time.
(7) Connect track bar to the axle bracket and
install the bolt. Do not tighten at this time.
(8) Install shock absorber and tighten bolts to 121
N´m (89 ft. lbs.).
(9) Install stabilizer bar link to the axle bracket.
Tighten the nut to 37 N´m (27 ft. lbs.).
(10) Install drag link and tie rod to the steering
knuckles and tighten the nuts to 88 N´m (65 ft. lbs.).
(11) Install ABS wheel speed sensors, if equipped.
Refer to 5 Brakes for procedures.
(12) Install rotors and brake calipers, refer to 5
Brakes for procedures.
(13) Connect the vent hose to the tube fitting.
(14) Connect vacuum hose and electrical connector
to disconnect housing.
(15) Install front propeller shaft.
(16) Check and add differential lubricant, if neces-
sary. Refer to Lubricant Specifications for lubricant
requirements.
(17) Install wheel and tire assemblies.
(18) Remove supports and lower the vehicle.
(19) Tighten upper suspension arm nuts at axle to
121 N´m (89 ft. lbs.). Tighten upper suspension arm
nuts at frame to 84 N´m (62 ft. lbs.).
(20) Tighten lower suspension arm nuts at axle to
84 N´m (62 ft. lbs.). Tighten the lower suspension
arm nuts at frame to 119 N´m (88 ft. lbs.).
(21) Tighten track bar bolt at the axle bracket to
176 N´m (130 ft. lbs.).
(22) Check front wheel alignment.
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. 3). 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 center 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 Backlash and Contact Pattern
in this section for additional information.
Compensation for pinion depth variance is
achieved with a select shim/slinger. The shims are
placed between the rear pinion bearing and the pin-
ion gear head (Fig. 4).
Fig. 3 PINION GEAR ID NUMBERS
1 - PRODUCTION NUMBERS
2 - PINION GEAR DEPTH VARIANCE
3 - GEAR MATCHING NUMBER
Fig. 4 SHIM LOCATIONS
1 - PINION GEAR DEPTH SHIM/SLINGER
2 - DIFFERENTIAL BEARING SHIM
BR/BEFRONT AXLE - 248FBI 3 - 19
FRONT AXLE - 248FBI (Continued)

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.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 the
required 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
3 - 20 FRONT AXLE - 248FBIBR/BE
FRONT AXLE - 248FBI (Continued)

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)