Dodge Dakota (R1). Manual - part 201

ferential pinion mate shaft is retained with a roll-
pin. Differential bearing preload and ring gear
backlash is adjusted by the use of shims (select thick-
ness). The shims are located between the differential
bearing cups and the axle housing. Pinion bearing

preload is set and maintained by the use of a collaps-
ible spacer.

OPERATION

The axle receives power from the transfer case

through the front propeller shaft. The front 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.

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. 1).

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.
2). 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.

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FRONT AXLE - C205F

DIAGNOSIS AND TESTING - AXLE

GEAR NOISE

Axle gear noise can be caused by insufficient lubri-

cant, incorrect backlash, tooth contact, worn/damaged
gears or the carrier housing not having the proper
offset and squareness.

Gear noise usually happens at a specific speed

range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.

When road testing, first warm-up the axle fluid by

driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the

peak-noise range. If the noise stops or changes
greatly:

• Check for insufficient lubricant.

• Incorrect ring gear backlash.

• Gear damage.
Differential side gears and pinions can be checked

by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.

BEARING NOISE

The axle shaft, differential and pinion bearings can

all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.

Pinion bearings have a constant-pitch noise. This

noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.

Worn or damaged differential bearings usually pro-

duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.

Axle shaft bearings produce noise and vibration

when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.

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:

• Damaged drive shaft.

• Missing drive shaft balance weight(s).

• Worn or out of balance wheels.

• Loose wheel lug nuts.

• Worn U-joint(s).

• Loose/broken springs.

• Damaged axle shaft bearing(s).

• Loose pinion gear nut.

• Excessive pinion yoke run out.

• Bent axle shaft(s).

Fig. 1 Differential Operation-Straight Ahead Driving

1 - STRAIGHT AHEAD DRIVING
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE

Fig. 2 Differential Operation-On Turns

1 - PINION GEARS ROTATE ON PINION SHAFT

FRONT AXLE - C205F

3 - 23

FRONT AXLE - C205F (Continued)

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:

• High engine idle speed.

• Transmission shift operation.

• Loose engine/transmission/transfer case mounts.

• Worn U-joints.

• Loose spring mounts.

• Loose pinion gear nut and yoke.

• Excessive ring gear backlash.

• Excessive 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.

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.

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FRONT AXLE - C205F

FRONT AXLE - C205F (Continued)

Condition

Possible Causes

Correction

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.

FRONT AXLE - C205F

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FRONT AXLE - C205F (Continued)

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