Dodge Durango (DN). Manual — part 225

with the scooter block against the pinion height block
(Fig. 41). When the dial probe contacts the arbor bar,
the dial pointer will turn clockwise. Bring dial
pointer back to zero against the arbor bar, do not
turn dial face. Continue moving the dial probe to the
crest of the arbor bar and record the highest reading.
If the dial indicator can not achieve the zero reading,
the rear bearing cup or the pinion depth gauge set is
not installed correctly.

(9) Select a shim equal to the dial indicator read-

ing plus the drive pinion gear depth variance number
marked on the shaft of the pinion gear using the
opposite sign on the variance number. For example, if
the depth variance is –2, add +0.002 in. to the dial
indicator reading.

(10) Remove the pinion depth gauge components

from the axle housing

DIFFERENTIAL BEARING PRELOAD AND GEAR
BACKLASH

Differential side bearing preload and gear backlash

is achieved by selective shims inserted between the
bearing cup and the axle housing. The proper shim
thickness can be determined using slip-fit Dummy
Bearings 8398 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, starting point shim thicknesses, and the
preload specification added together. The gear back-
lash 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 side of the differential (Fig.
42).

Fig. 40 Gauge Tools In Housing

1 – ARBOR DISC
2 – PINION BLOCK
3 – ARBOR
4 – PINION HEIGHT BLOCK

Fig. 41 Pinion Gear Depth Measurement

1 – ARBOR
2 – SCOOTER BLOCK
3 – DIAL INDICATOR

Fig. 42 Axle Adjustment Shim Locations

1 – PINION GEAR DEPTH SHIM
2 – DIFFERENTIAL BEARING SHIM-PINION GEAR SIDE
3 – RING GEAR
4 – DIFFERENTIAL BEARING SHIM-RING GEAR SIDE
5 – COLLAPSIBLE SPACER

3 - 50

C205F AXLE

DN

ADJUSTMENTS (Continued)

SHIM SELECTION

NOTE: It is difficult to salvage the differential side
bearings during the removal procedure. Install
replacement bearings if necessary.

(1) Remove side bearings from differential case.
(2) Install ring gear, if necessary, on differential

case and tighten bolts to specification.

(3) Install Dummy Side Bearings 8398 on differen-

tial case.

(4) Install differential case in axle housing.
(5) Insert Dummy Shims 8107 (0.118 in. (3.0 mm))

starting point shims between both dummy bearings
and the axle housing (Fig. 43).

(6) Install the marked bearing caps in their correct

positions. Install and snug the bolts.

(7) Using a dead-blow type mallet, seat the differ-

ential dummy bearings to each side of the axle hous-
ing (Fig. 44) and (Fig. 45).

(8) Thread guide stud L-4438 into rear cover bolt

hole below ring gear (Fig. 46).

(9) Attach dial indicator C-3339 to guide stud.

Position the dial indicator plunger on a flat surface
on a ring gear bolt head (Fig. 46).

Fig. 43 Insert Starting Point Shims

1 – SPECIAL TOOL 8107
2 – AXLE HOUSING
3 – DIFFERENTIAL CASE
4 – SPECIAL TOOL D-348

Fig. 44 Seat Pinion Side Dummy Side Bearing

1 – MALLET
2 – AXLE HOUSING
3 – DIFFERENTIAL CASE

Fig. 45 Seat Ring Gear Side Dummy Bearing

1 – AXLE HOUSING
2 – MALLET
3 – DIFFERENTIAL CASE

DN

C205F AXLE

3 - 51

ADJUSTMENTS (Continued)

(10) Push firmly and hold differential case to pin-

ion side of axle housing (Fig. 47).

(11) Zero dial indicator face to pointer.
(12) Push firmly and hold differential case to ring

gear side of the axle housing (Fig. 48).

(13) Record dial indicator reading.

(14) Add the dial indicator reading to the starting

point shim thicknesses to determine the total shim
thickness necessary to achieve zero differential end play.

(15) Add 0.008 in. (0.2 mm) to the zero end play

total. This new total represents the thickness of
shims necessary to compress, or preload the new
bearings when the differential is installed.

(16) Rotate dial indicator out of the way on guide

stud.

(17) Remove differential case, dummy bearings,

and starting point shims from the axle housing.

(18) Install the pinion in the axle housing. Install

the companion flange and establish the correct pinion
rotating torque.

(19) Install differential case and dummy bearings

in axle housing with a single Dummy Shim 8107 on
the ring gear side of the axle and tighten retaining
cap bolts.

(20) Position the dial indicator plunger on a flat

surface between the ring gear bolt heads (Fig. 46).

(21) Push and hold differential case toward pinion.
(22) Zero dial indicator face to pointer.
(23) Push and hold differential case to ring gear

side of the axle housing.

(24) Record dial indicator reading.
(25) Subtract 0.002 in. (0.05 mm) from the dial

indicator reading to compensate for backlash between
ring and pinion gears. Add the resulting measure-
ment to the thickness of the single starting point
shim. This total is the thickness of shim required to
achieve proper backlash.

(26) Subtract the backlash shim thickness from

the total preload shim thickness. The remainder is
the shim thickness required on the pinion side of the
axle housing.

Fig. 46 Differential Side play Measurement

1 – DIFFERENTIAL CASE
2 – AXLE HOUSING
3 – SPECIAL TOOL C-3288–B
4 – SPECIAL TOOL C-3339

Fig. 47 Hold Differential Case and Zero Dial

Indicator

1 – FORCE DIFFERENTIAL CASE TO PINION GEAR SIDE
2 – SPECIAL TOOL C-3288–B
3 – SPECIAL TOOL C-3339
4 – ZERO DIAL INDICATOR FACE

Fig. 48 Hold Differential Case and Read Dial

Indicator

1 – READ DIAL INDICATOR
2 – FORCE DIFFERENTIAL CASE TO RING GEAR SIDE
3 – AXLE HOUSING

3 - 52

C205F AXLE

DN

ADJUSTMENTS (Continued)

(27) Rotate dial indicator out of the way on guide

stud.

(28) Remove differential case, dummy bearings,

and dummy shim from axle housing.

(29) Install new side bearing cones and cups on

differential case.

(30) Install spreader W-129-B, utilizing Adapter

Plates 8142-A, on axle housing and spread axle open-
ing enough to receive differential case.

(31) Place the side bearing shims in the axle hous-

ing against the axle housing shoulder.

(32) Install the differential case in the axle hous-

ing.

(33) Rotate the differential case several times to

seat the side bearings.

(34) Position the indicator plunger against a ring

gear tooth (Fig. 49).

(35) Push and hold ring gear upward while not

allowing the pinion gear to rotate.

(36) Zero dial indicator face to pointer.
(37) 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 differential housing to the
other (Fig. 50).

(38) 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 the

Gear Contact Pattern Analysis procedure.

GEAR CONTACT PATTERN ANALYSIS

The ring gear and pinion teeth contact patterns

will show if the pinion depth is correct in the axle
housing. 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) Using a boxed end wrench on a 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.
51) and adjust pinion depth and gear backlash as
necessary.

Fig. 49 Ring Gear Backlash Measurement

1 – DIAL INDICATOR

Fig. 50 Backlash Shim Adjustment

DN

C205F AXLE

3 - 53

ADJUSTMENTS (Continued)