Dodge RAM TRUCK 1500 1995 Service Manual page 127

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 80 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 gear shaft bore will also cause low speed
knock.
WiBRAIiON
Vibration at the rear of the vehicle is usually
caused by a:
© Damaged drive shaft
© Missing drive shaft balance weight
3 Worn, out-of-balance wheels
© Loose wheel lug nuts
© Worn U-joint
® Loose spring clamp bolts
^ Loose/broken springs
* Damaged axle shaft bearings
© Loose pinion gear nut
© Excessive pinion yoke run out
© Bent axle shaft
Check for loose or damaged front end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear end vi­
bration. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined be­
fore starting any repair.
Refer to Group 22, Wheels and Tires for additional
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
© Loose engine/transmission/transfer case mounts
o Worn U-joints
© Loose spring mounts
© Loose pinion gear nut and yoke
o Excessive ring gear backlash
o Excessive differential 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 ve­
hicle 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.
REAR AXLE ALIGNMENT
The following procedure can be used to determine
if abnormal rear tire tread wear is the result of a
bent or deformed rear axle shaft.
(1) Raise both rear wheels off the surface with a
frame contact hoist.
(2) Attach a one-inch long piece of masking tape at
the center of each tire tread for use as reference
marks.
(3) Rotate the rear wheels until both reference
marks face the front of the vehicle. Measure the dis­
tance between the outside edges of the two pieces of
tape. Record this measurement as the front of tire
(FTR) measurement.
(4) Rotate the rear wheels until both reference
marks face the rear of the vehicle. Measure the dis­
tance between the outside edges of the two pieces of
tape. Record this measurement as the rear of tire
(RTR) measurement.
(5) Subtract the (RTR) measurement from the
(FTR) measurement to obtain the amount of wheel
toe. The acceptable rear wheel toe-in position is 1/16
inch (1.6 mm) to 3/16 inch (4.8 mm) toe-out.
(6) Rotate the rear wheels until the reference
marks are facing downward. Measure the distance
between the outside edges of the two pieces of tape.
Record this measurement as the bottom of tire (BTR)
measurement.
(7) Average the (FTR) and the (RTR) distance mea­
surements. Subtract the (BTR) measurement from
this average distance to obtain the camber. The ac­
ceptable amount of camber is 1/16 inch to 3/32 inch
(1.6. to 2.4 mm).
(FTE + BTR) DIVIDED BY 2 (TWO) MINUS
BTR EQUALS CAMBER
If the (BTR) distance measurement is less
than the average FTR and RTR distance mea­
surement, the camber will be positive ( 4- ), If
the (BTR) distance measurement is greater
than the average FTR and RTR distance, the
camber will be negative ( - ).
If the toe position or camber is not acceptable, a
bent or deformed rear axle shaft is most likely the
cause.
JMITED SLIP DIFFERENTIAL
Under normal traction conditions, engine torque is
divided evenly. With low-traction surfaces, engine
torque is transferred to the wheel with the most tire
traction. When diagnosing a limited-slip differential
problem condition, the wheel with the least traction
can continue spinning.
The most common problem is a chatter noise when
turning corners. Check for incorrect or contaminated
lubricant. Replace the gear lubricant if necessary,
o With Trac-Lok or Power-Lok differentials MO­
PAR friction modifier must be added to the lubricant.
This will correct the condition in most instances. If
the chatter persists, clutch damage could have oc­
curred.
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.