Drive Shaft Noises
When operating a vehicle to verify a complaint.
keep in mind that other components could be at fault. A
worn wheel bearing, squeaking spring, defective tire.
transmission, or differential troubles could be at fault.
You must use your knowledge of each system to detect
which component is causing the trouble.
Drive shaft noises are usually caused by worn U-
joints, slip joint wear, or a faulty center support
bearing. Drive shaft noises and possible causes are as
Grinding and squeaking from the drive shaft is
frequently caused by worn universal joints. The joints
become dry, causing the rollers to wear. The
unlubricated, damaged rollers then produce a grinding
or squeaking sound, as they operate on the scored cap
and cross surfaces.
A clunking sound, when going from acceleration
to deceleration or deceleration to acceleration, may be
caused by slip yoke problems. The splines may be worn.
The yoke transmission extension housing bushing may
also be worn. This will let the yoke move up and down
with changes in drive line torque. An excessively worn
U-joint or differential problem can also cause a similar
A whining sound from the drive shaft is
sometimes caused by a dry, worn center support
bearing. Since this bearing makes complete revolutions.
it will make a different sound than a bad universal joint.
A high pitched. more constant, whine will usually come
from a faulty center support bearing.
Any other abnormal sound should be traced using
your knowledge of mechanics. a stethoscope, and the
vehicles service manual troubleshooting chart.
Drive Shaft Inspection
To inspect the drive shaft for wear or damage, raise
the vehicle and place it on jack stands. Look for
undercoating or mud on the drive shaft. Check for
missing balance weights, cracked welds, and other
drive shaft problems.
To check for working U-joints, wiggle and rotate
each U-joint back and forth. Watch the universal joint
carefully. Try to detect any play between the cross and
the yoke. If the cross moves inside the yoke, the U-joint
is worn and needs to be replaced.
Also, wiggle the slip yoke up and down. If it moves
in the transmission bushing excessively, either the
yoke or the bushing is worn. Inspect the rear yoke bolts
for tightness. Make sure the rear motor mount is NOT
broken. Look at any condition that can upset the
operation of the drive shaft.
If after a thorough check of the drive shaft you fail
to determine the problem, notify the shop supervisor.
The drive shaft may require detailed measuring (drive
shaft runout and drive shaft angle) or have its balance
Universal Joint Service
The universal joints on many automotive
vehicles are factory lubricated. However, construc-
tion equipment have universal joints that have
lubrication fittings that should be lubricated at
Service to universal joints that are factory
lubricated is limited to replacement when signs of
excessive wear are present. The universal joints
provided with lubrication fittings are only lubricated
with a hand operated low-pressure grease guns. Use of
a high-pressure grease gun will damage the seals,
resulting in early failure of the universal joint.
Another area to be concerned with when servicing
the universal joints is the slip yoke (joint). Slip yokes
may be lubricated from the transmission or lubricated
through a lubrication fitting.
Always consult the manufacturers service
manual for lubrication intervals and proper
lubricants to be used.
A worn universal joint is the most common drive
line problem, causing squeaking, grinding, clunking,
or clicking sounds. The grease inside the joint can dry
out. The roller bearings will wear small indentations in
the cross. When the bearings try to roll over these
dents, a loud metal-on-metal grinding or chirp sound
Quite often, a worn U-joint is discovered when the
transmission is placed in REVERSE. When the vehicle
is backed up, the roller bearing is forced over the wear
indentation against normal rotation. When this occurs,
the rollers will catch on the sharp edges in the worn
joint, causing even a louder sound.
UNIVERSAL JOINT DISASSEMBLY.The
universal joint may require removal and disassembly
to enable you to check the condition of the joint