Drive/Propeller Shaft: Testing and Inspection

PROPELLER SHAFT

VIBRATION

Tires that are out-of-round,or wheels that are unbalanced, will cause a low frequency vibration.

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

Driveline vibration can also result from loose or damaged engine mounts.

Propeller shaft vibration increases as the vehicle speed is increased. A vibration that occurs within a specific speed range is not usually caused by a propeller shaft being unbalanced. Defective universal/CV joints, or an incorrect propeller shaft angle, are usually the cause of such a vibration.

DRIVELINE VIBRATION






BALANCE





If propeller shaft is suspected of being out of balance, use the following procedure.

NOTE: Indexing propeller shaft 180 degrees relative to the yoke may eliminate some vibrations.

1. Raise and support vehicle.
2. Clean all foreign material from the propeller shaft.
3. Inspect propeller shaft for missing balance weights, broken welds and bent areas. If propeller shaft is bent, it must be replaced.
4. Inspect universal joints/CV joints for wear.
5. Check propeller shaft bolt torques.
6. Remove wheels and install lug nuts to retain brake rotors.
7. Mark and number the shaft six inches from the pinion flange end at four positions 90 degrees apart.
8. Run and accelerate vehicle until vibration occurs. Note at what speed the vibration occurred. Stop the engine.
9. Install a screw clamp at position (1).





10. Start engine and check vibration. If there is little or no change move the clamp to the next positions and repeat vibration test.

NOTE: If there is no difference in vibration at this positions, the vibration may not be the propeller shaft.

11. If vibration decreased, install a second clamp (1) and repeat the test.





12. If additional clamp causes an additional vibration, separate the clamps 1/2 inch (1) above and below the mark. Repeat the vibration test.
13. Increase distance between the clamp screws (1) (2) and repeat test, until the least amount of vibration is noticed. Bend the slack end of the clamps so screws will not loosen.
14. If vibration remains unacceptable, repeat the procedure to the front end of the propeller shaft.

RUNOUT

1. Remove dirt, rust, paint, and undercoating from the propeller shaft surface where the dial indicator will contact the shaft.
2. The dial indicator must be installed perpendicular to the shaft surface.
3. Measure runout at the center and ends of the shaft sufficiently far away from weld areas to ensure that the effects of the weld process will not enter into the measurements.
4. Refer to Runout Specifications chart.
5. If the propeller shaft runout is out of specification, remove the propeller shaft, index the shaft 180°, and re-install the propeller shaft. Measure shaft runout again.
6. If the propeller shaft runout is now within specifications, mark the shaft and yokes for proper orientation.
7. If the propeller shaft runout is not within specifications, verify that the runout of the transmission/transfer case and axle are within specifications. Correct as necessary and re-measure propeller shaft runout.
8. Replace the propeller shaft if the runout still exceeds the limits.
RUNOUT SPECIFICATIONS