Dodge Durango (DN). Manual — part 228

Fig. 3 9 1/4 Axle

3 - 62

8 1/4 AND 9 1/4 AXLE

DN

DESCRIPTION AND OPERATION (Continued)

AXLE IDENTIFICATION

The axle differential cover can be used for identifi-

cation of the axle and (Fig. 4). A ratio tag is attached
to the differential cover.

OPERATION

The axle receives power from the transmission/

transfer case through the rear propeller shaft. The
rear propeller shaft is connected to the pinion gear
which rotates the differential through the gear mesh
with the ring gear bolted to the differential case. The
engine power is transmitted to the axle shafts
through the pinion mate and side gears. The side
gears are splined to the axle shafts.

LUBRICANT

DESCRIPTION

Multi-purpose, hypoid gear lubricant should be

used for rear axles with a standard differential. The
lubricant should have a MIL-L-2105C and API GL 5
quality specifications.

Trac-Lok differentials require the addition of 5 oz.

of friction modifier to the axle lubricant after service.
The 8 1/4 axle lubricant capacity is 2.22 L (4.7 pts.)
total, including the friction modifier, if necessary. The
9 1/4 axle lubricant capacity is 2.32 L (4.9 pts.) total,
including friction modifier, if necessary.

NOTE: If the rear axle is submerged in water, the
lubricant must be replaced immediately. Avoid the
possibility of premature axle failure resulting from
water contamination of the lubricant.

1 – HUB
2 – AXLE SHAFT
3 – VENT FITTING
4 – DIFFERENTIAL HOUSING
5 – CUP
6 – PINION FRONT BEARING CONE
7 – NUT
8 – WASHER
9 – COMPANION FLANGE
10 – SEAL
11 – AXLE SHAFT
12 – HUB
13 – STUD
14 – BEARING CUP
15 – PINION REAR BEARING CONE
16 – DIFFERENTIAL BEARING
17 – ADJUSTER
18 – LOCK
19 – BOLT
20 – BEARING CAP
21 – CAP BOLT
22 – BEARING CUP
23 – THRUST WASHER
24 – SIDE GEAR
25 – C-LOCK
26 – DIFFERENTIAL POSITIONS
27 – THRUST WASHER
28 – COVER

29 – PLUG
30 – COVER BOLT
31 – WASHER
32 – CLIP
33 – SIDE GEAR
34 – THRUST WASHER
35 – DIFFERENTIAL BEARING CONE
36 – C-LOCK
37 – BOLT
38 – LOCK
39 – BEARING CUP
40 – ADJUSTER
41 – BEARING CUP
42 – BOLT
43 – PINION MATE SHAFT
44 – EXCITER RING
45 – DIFFERENTIAL CASE
46 – RING GEAR BOLT
47 – RING GEAR
48 – PINION
49 – PINION GEAR DEPTH SHIM
50 – BEARING PRELOAD COLLAPSIBLE SPACER
51 – SEAL
52 – AXLE SHAFT BEARING
53 – AXLE SHAFT TUBE
54 – AXLE TUBE
55 – AXLE SHAFT BEARING
56 – SEAL

Fig. 4 Differential Cover 9 1/4 Inch Axle

1 – DIFFERENTIAL COVER
2 – RATIO TAG
3 – PUSH-IN FILL PLUG

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8 1/4 AND 9 1/4 AXLE

3 - 63

DESCRIPTION AND OPERATION (Continued)

STANDARD DIFFERENTIAL

DESCRIPTION

The differential gear system divides the torque

between the axle shafts. It allows the axle shafts to
rotate at different speeds when turning corners.

Each differential side gear is splined to an axle

shaft. The pinion gears are mounted on a pinion
mate shaft and are free to rotate on the shaft. The
pinion gear is fitted in a bore in the differential case
and is positioned at a right angle to the axle shafts.

OPERATION

In operation, power flow occurs as follows:
• The pinion gear rotates the ring gear

• The ring gear (bolted to the differential case)

rotates the case

• The differential pinion gears (mounted on the

pinion mate shaft in the case) rotate the side gears

• The side gears (splined to the axle shafts) rotate

the shafts

During straight-ahead driving, the differential pin-

ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 5).

When turning corners, the outside wheel must

travel a greater distance than the inside wheel to
complete a turn. The difference must be compensated
for to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential
allows the axle shafts to turn at unequal speeds (Fig.
6). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
now rotate around the pinion mate shaft in opposite
directions. This allows the side gear and axle shaft
attached to the outside wheel to rotate at a faster
speed.

TRAC-LOK

Y DIFFERENTIAL

DESCRIPTION

In a standard differential, if one wheel spins, the

opposite wheel will generate only as much torque as
the spinning wheel.

In the Trac-lok

y differential, part of the ring gear

torque is transmitted through clutch packs which
contain multiple discs. The clutches will have radial
grooves on the plates, and concentric grooves on the
discs or bonded fiber material that is smooth in
appearance.

Fig. 5 Differential Operation—Straight Ahead Driving

1 – IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT

100% OF CASE SPEED

2 – PINION GEAR
3 – SIDE GEAR
4 – PINION GEARS ROTATE WITH CASE

Fig. 6 Differential Operation—On Turns

1 – PINION GEARS ROTATE ON PINION SHAFT

3 - 64

8 1/4 AND 9 1/4 AXLE

DN

DESCRIPTION AND OPERATION (Continued)

OPERATION

In operation, the Trac-lok

y clutches are engaged

by two concurrent forces. The first being the preload
force

exerted

through

Belleville

spring

washers

within the clutch packs. The second is the separating
forces generated by the side gears as torque is
applied through the ring gear (Fig. 7).

The Trac-lok

y design provides the differential

action needed for turning corners and for driving
straight ahead during periods of unequal traction.
When one wheel looses traction, the clutch packs
transfer additional torque to the wheel having the
most traction. Trac-lok

y differentials resist wheel

spin on bumpy roads and provide more pulling power
when one wheel looses traction. Pulling power is pro-
vided continuously until both wheels loose traction. If
both wheels slip due to unequal traction, Trac-lok

y

operation is normal. In extreme cases of differences
of traction, the wheel with the least traction may
spin.

DIAGNOSIS AND TESTING

GENERAL INFORMATION

Axle bearing problem conditions are usually caused

by:

• Insufficient or incorrect lubricant.

• Foreign matter/water contamination.

• Incorrect bearing preload torque adjustment.

• Incorrect backlash.
Axle gear problem conditions are usually the result

of:

• Insufficient lubrication.

• Incorrect or contaminated lubricant.

• Overloading (excessive engine torque) or exceed-

ing vehicle weight capacity.

• Incorrect clearance or backlash adjustment.
Axle component breakage is most often the result

of:

• Severe overloading.

• Insufficient lubricant.

• Incorrect lubricant.

• Improperly tightened components.

• Differential housing bores not square to each

other.

Fig. 7 Trac-lok

Y

Limited Slip Differential Operation

1 – CASE
2 – RING GEAR
3 – DRIVE PINION
4 – PINION GEAR
5 – MATE SHAFT
6 – CLUTCH PACK
7 – SIDE GEAR
8 – CLUTCH PACK

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8 1/4 AND 9 1/4 AXLE

3 - 65

DESCRIPTION AND OPERATION (Continued)