> Hey everybody,
>
> I am trying to diagnose a problem with my truck. What would the symptoms
of an
> imbalanced driveshaftm worn transmission bearing, or u-joint be? I
reasoned
> myself into thinking my problem may be one of those, but I would feel
better
> about tearing stuff apart if someone could back me up ;)
Mike,
Worn ujoints on the driveshaft will have a clunking noise when accelerating
from a dead stop and/or will also have a squealing noise, as the driveshaft
spins around. You can get under your truck and grab the driveshaft(near the
ujoint) with your hand and try to physically push/pull the driveshaft up and
down or side to side. Movement or play will indicate a worn out ujoint. An
imbalanced driveshaft will give you some nasty ole vibrations at various
speeds. Try having your tires balanced/rotated first if you are feeling
vibrations.
I found this on a website:
"Driveline vibrations can be caused by several problems. Worn universal
joints or a driveline that is out of balance are often the problem, but
driveline angle can cause a balanced driveline with good U-joints to
vibrate. If the U-joints are bad, they can cause several different noises
from squeaking, to clunking, to grinding, to vibrations. If the driveline is
out of balance, it will vibrate with a steady pitch that increases as the
vehicle speed increases. If the pinion shaft is out of alignment and not
parallel to the transmission yoke, the difference in the angles between the
front and back U-joints can cause the driveline to vibrate. If the vibration
is due to improper angles, it will create a cyclic sound that increases and
decreases in intensity and is not steady. An out-of-alignment problem can
also be identified by the change in the noise when accelerating or
decelerating. As the pinion yoke torques up from acceleration or down from
deceleration, the rear U-joint angle changes and causes the vibration to
change."
also found this:
"Universal joints: Drive shaft service on rear-wheel drive and four-wheel
drive vehicles is pretty much limited to universal joint (U-joint)
replacement for most shops. This does not mean everything else should be
ignored, however. Driveshaft problems have two distinct symptoms that can
make diagnosis easy. While tire balance problems are speed sensitive,
driveshaft vibrations are not. A binding U-joint or damaged driveshaft will
make a vibration that will shake the floor of the vehicle. While high speed
can make it worse, it will be present at most speeds. A severely damaged
U-joint can make a repeated 'chirping' or squeak at very low speeds. On many
four-wheel drive vehicles the front drive shaft does not spin in two-wheel
drive, so a complaint when in four-wheel drive would be the only reason to
suspect a front driveshaft problem. The best way to check the U-joints for
binding is simply to remove the driveshaft and feel how easily they can be
rotated in both directions by hand. Don't forget that a dented driveshaft or
a weight knocked off balance can create the same vibrations as a binding
U-joint.
The style of the bearing cup retention must be determined before U-joint
service. Besides internal and external snap ring -- or 'c' -- clips, some
OEM U-joints are secured with an injected nylon ring. This type of retainer
is simply sheared off when the bearing cup is pressed out of the yoke. Nylon
injected U-joints can not be reassembled once removed. When installing a new
U-joint with a grease fitting, it is best to locate the fitting where it
will be under compression and not tension because this is the weakest part
of the joint. If the slip joint is separated for service, it must be marked
to keep the relationship between front and rear U-joints the same. On
modified vehicles, the operating angle of both U-joints need to be equal so
they can balance out the inherent speed changes when they rotate at an
angle."
Good Luck, hope this helps somewhat.
Kyle
93 Dakota 4x4 V6
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