DIAGNOSIS AND TESTING
PROPELLER SHAFT
PROPELLER SHAFT VIBRATION
| Drive Condition | Possible Cause | Correction |
| Propeller Shaft Noise | 1. Undercoating or other foreign material on shaft. | 1. Clean exterior of shaft and wash with solvent. |
| 2. Loose U-joint clamp screws. | 2. Install new clamps and screws and tighten to proper torque. | |
| 3. Loose or bent U-joint yoke or excessive runout. | 3. Install new yoke. | |
| 4. Incorrect driveline angularity. | 4. Measure and correct driveline angles. | |
| 5. Worn joint. | 5. Install new joint. | |
| 6. Propeller shaft damaged or out of balance. | 6. Installl new propeller shaft. | |
| 7. Broken rear spring. | 7. Install new rear spring. | |
| 8. Excessive runout or unbalanced condition. | 8. Re-index propeller shaft, test, and evaluate. | |
| 9. Excessive drive pinion gear shaft runout. | 9. Re-index propeller shaft and evaluate. | |
| 10. Excessive axle yoke deflection. | 10. Inspect and replace yoke if necessary. | |
| 11. Excessive transfer case runout. | 11. Inspect and repair as necessary. | |
| U-Joint Noise | 1. Loose U-joint clamp screws. | 1. Install new clamps and screws and tighten to proper torque. |
| 2. Lack of lubrication. | 2. Replace joints as necessary. |
Out-of-round tire or wheels that are 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 180° relative to the yoke 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 universal joints for wear, properly 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 yoke 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 with a screw driver (2).
9. Start the engine and check for vibration. If there is little or no change in vibration, move the clamp to the next positions. 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 decreased, install a second clamp 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.
RUNOUT
| Front of Shaft | 0.020 in. (0.50 mm) |
| Center of Shaft | 0.025 in. (0.63 mm) |
| Rear of Shaft | 0.020 in. (0.50 mm) |
NOTE: Measure front/rear runout approximately 3 inches (76 mm) from the weld seam at each end of the shaft tube for tube lengths over 30 inches. For tube lengths under 30 inches, the maximum allowed runout is 0.020 in. (0.50 mm) for the full length of the tube. | |
1. Clean 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 away from weld areas to ensure an accurate measurements.
4. Refer to Runout Specifications chart.
5. If propeller shaft runout is out of specification, remove propeller shaft. Index the shaft 180 degrees and measure shaft runout again.
6. If propeller shaft runout is now within specifications, mark the shaft and yokes for proper orientation.
7. If propeller shaft runout is not within specifications, check runout of the transmission/transfer case and axle. Correct as necessary and repeat propeller shaft runout measurement.
8. Replace propeller shaft if the runout still exceeds the limits.