Drive/Propeller Shaft: Testing and Inspection

PROPELLER SHAFT

PROPELLER SHAFT VIBRATION





A out of round tire or wheel that is out of balance, will cause a low frequency vibration.

Brake rotors that are unbalanced will cause a harsh, low frequency vibration.

Driveline vibration can be caused by loose or damaged engine mounts.

Propeller shaft vibration increases with vehicle speed. A vibration that occurs at a specific speed is not usually caused by a out of balance propeller shaft. Worn universal joints or an incorrect propeller shaft angle, can cause such a vibration.

BALANCE





NOTE: Indexing the propeller shaft (1) 90° relative to the flange (2) may eliminate some vibrations.





1. Raise the vehicle.
2. Clean all the foreign material from the propeller shaft and universal joints.
3. Inspect propeller shaft for missing balance weights, broken welds, and bent areas.

NOTE: If the propeller shaft is bent, it must be replaced.

4. Inspect joints for wear, proper installation and correct alignment with the shaft.
5. Remove wheels and tires and install wheel lug nuts to retain brake drums/rotors.
6. Mark and number the shaft six inches from the pinion flange end at four positions 90 degrees apart.
7. Run and accelerate the vehicle until vibration occurs. Note the intensity and speed the vibration occurred. Stop the engine.
8. Position one screw clamp (1) on the propeller shaft (2) at one of the 90 degree marks.
9. Start the engine and check for vibration. If there is little or no change in vibration, move the clamp to the next mark. Repeat the vibration test. If there is no difference in vibration at the other positions, the source of the vibration may not be propeller shaft.




10. If vibration is decreased, install a second clamp (1) in the same position on the propeller shaft (2) and repeat the test.




11. If the additional clamp causes an additional vibration, separate the clamps (1) 1/4 inch above and below the mark. Repeat the vibration test.
12. Increase distance between the clamps and repeat the test until the amount of vibration is at the lowest level. Bend the slack end of the clamps so the screws will not loosen.
13. If vibration remains unacceptable, repeat the procedure to the front end of the propeller shaft.
14. Install wheel and tires, and lower vehicle.