Tools Required
J 38792-A Electronic Vibration Analyzer
(EVA) 2
Notice: Do not fill the propeller shaft with foam, oil, or any other substance
in order to correct a vibration. Filling the propeller shaft is only effective
in reducing an unrelated condition called Torsional Rattle. Filling the propeller
shaft should only be done in strict adherence to the procedure outlined in
corporate bulletins that address Torsional Rattle. Failure to follow the correct
procedure will induce a vibration and/or affect the structural integrity of
the propeller shaft. The propeller shaft will then have to be replaced.
- Support the vehicle on a hoist or jackstands. Support the axle(s) at
curb height. Refer to
Lifting and Jacking the Vehicle
in General Information.
- Turn the ignition ON.
- Place the transmission in NEUTRAL.
- Remove the rear tire/wheel assemblies. Refer to
Tire and Wheel Removal and Installation
in Tires and Wheels.
- Remove the brake drums. Refer to
Brake Drum Replacement
in Drum Brakes.
- Hold the J 38792-A
sensor against the pinion nose.
Notice: Do not depress the brake pedal with the brake rotors and/or the brake
drums removed, or with the brake calipers repositioned away from the brake
rotors, or damage to the brake system may result.
- Start the vehicle.
- Place the transmission in the highest forward gear.
- Have an assistant accelerate and decelerate the vehicle through the speed
range at which the vibration was first noted during the Vibration Analysis --
Road Testing procedure.
- If a vibration is present, note the J 38792-A
reading during acceleration or deceleration.
- Note as to whether or not the pinion nose vibrates under load during
the acceleration or deceleration.
- If the vibration is not reproduced, reinstall the brake rotors and the
wheel/tire assemblies to put an additional load on the system. Check the components
again while an assistant maintains the vehicle at the vibration concern speed.
- If the vibration is still not reproduced, lightly apply the brakes to
further load the system while maintaining the vibration concern speed.
- If the pinion nose vibrates under acceleration or deceleration, and other
driveline components have been eliminated as a cause, the vibration may be an internal
axle problem.