Dodge Durango (DN). Manual — part 229
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 companion flange
nut.
6. Tighten the pinion companion flange
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.
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.
3 - 66
8 1/4 AND 9 1/4 AXLE
DN
DIAGNOSIS AND TESTING (Continued)
Condition
Possible Causes
Correction
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 companion flange.
5. Replace companion flange 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.
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.
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.
DN
8 1/4 AND 9 1/4 AXLE
3 - 67
DIAGNOSIS AND TESTING (Continued)
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 a:
• 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 nut.
• Excessive companion flange run out.
• Bent 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 Group 22, Wheels and Tires, for additional
vibration information.
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 nut and companion flange.
• 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.
TRAC–LOK
Y DIFFERENTIAL NOISE
The most common problem is a chatter noise when
turning corners. Before removing a Trac-lok
y unit
for repair, drain, flush and refill the axle with the
specified lubricant. Refer to Lubricant change in this
Group.
A container of Mopar
t Trac-loky Lubricant (fric-
tion modifier) should be added after repair service or
during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
TRAC–LOK
Y TEST
WARNING: WHEN SERVICING VEHICLES WITH A
TRAC–LOK
Y
DIFFERENTIAL DO NOT USE THE
ENGINE TO TURN THE AXLE AND WHEELS. BOTH
REAR WHEELS MUST BE RAISED AND THE VEHI-
CLE
SUPPORTED.
A
TRAC–LOK
Y
AXLE
CAN
EXERT ENOUGH FORCE IF ONE WHEEL IS IN CON-
TACT WITH A SURFACE TO CAUSE THE VEHICLE
TO MOVE.
3 - 68
8 1/4 AND 9 1/4 AXLE
DN
DIAGNOSIS AND TESTING (Continued)
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.
(4) Remove wheel and bolt Special Tool 6790 to
studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 8).
(6) If rotating torque is less than 22 N·m (30 ft.
lbs.) or more than 271 N·m (200 ft. lbs.) on either
wheel the unit should be serviced.
SERVICE PROCEDURES
LUBRICANT CHANGE
(1) Raise and support the vehicle.
(2) Remove the lubricant fill hole plug from the
differential housing cover.
(3) Remove the differential housing cover and
drain the lubricant from the housing.
(4) Clean the housing cavity with a flushing oil,
light engine oil, or lint free cloth. Do not use water,
steam, kerosene, or gasoline for cleaning.
(5) Remove the original sealant from the housing
and cover surfaces.
(6) Apply a bead of Mopar
t Silicone Rubber Seal-
ant, or equivalent, to the housing cover (Fig. 9).
Install the housing cover within 5 minutes
after applying the sealant.
(7) Install the cover and any identification tag.
Tighten the cover bolts to 41 N·m (30 ft. lbs.) torque.
(8) For Trac–lok
y differentials, a quantity of
Mopar
t Trac–loky lubricant (friction modifier), or
equivalent, must be added after repair service or a
lubricant change. Refer to the Lubricant Specifica-
tions section of this group for the quantity necessary.
(9) Fill differential with Mopar
t Hypoid Gear
Lubricant, or equivalent, to bottom of the fill plug
hole. Refer to the Lubricant Specifications section of
this group for the quantity necessary.
CAUTION: Overfilling the differential can result in
lubricant foaming and overheating.
(10) Install the fill hole plug and lower the vehicle.
(11) Trac–lok
y
differential
equipped
vehicles
should be road tested by making 10 to 12 slow figure-
eight turns. This maneuver will pump the lubricant
through the clutch discs to eliminate a possible chat-
ter noise complaint.
REMOVAL AND INSTALLATION
REAR AXLE
REMOVAL
(1) Raise and support the vehicle.
(2) Position a suitable lifting device under the
axle.
(3) Secure axle to device.
(4) Remove the wheels and tires.
(5) Secure brake drums to the axle shaft.
(6) Remove the RWAL sensor from the differential
housing, if necessary. Refer to Group 5, Brakes, for
proper procedures.
Fig. 8 Trac-lok
Y
Test —Typical
1 – SPECIAL TOOL 6790 WITH BOLT IN CENTER HOLE
2 – TORQUE WRENCH
Fig. 9 Apply Sealant
1 – SEALANT
2 – AXLE HOUSING COVER
DN
8 1/4 AND 9 1/4 AXLE
3 - 69
DIAGNOSIS AND TESTING (Continued)
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