- Remove dirt, rust, paint, and undercoating from the propeller shaft surface where the dial indicator will contact the shaft.
- The dial indicator must be installed perpendicular to the shaft surface.
- Measure run-out 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.
- Replace the propeller shaft if the run-out exceeds 0.020 in. (0.50mm) at the front of shaft, 0.025 in. (0.63mm) at the center of the shaft or 0.020 in. (0.50mm) at the rear of the shaft.
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 joints, or an incorrect propeller shaft angle, are usually the cause of such a vibration.
If propeller shaft is suspected of being unbalanced, it can be verified with the following procedure.
- Raise and safely support the vehicle securely on jackstands.
- Clean all the foreign material from the propeller shaft and the universal joints.
- Inspect the propeller shaft for missing balance weights, broken welds, and bent areas. If the propeller shaft is dented or bent, it must be replaced.
- Inspect the universal joints to ensure that they are not worn, are properly installed, and are correctly aligned with the shaft.
- Check the universal joint clamp bolt torque.
- Remove the wheels and tires. Install the wheel lug nuts to retain the brake drums or rotors.
- Mark and number the shaft 6 inches (15cm) from the yoke end at four positions 90º apart.
- Run and accelerate the vehicle until vibration occurs. Note the intensity and speed the vibration occurred. Stop the engine.
- Install a screw clamp at any position.
- Start the engine and re-check for vibration. If there is little or no change in vibration, move the clamp to one of the other three 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.
- If the vibration decreased, install a second clamp and repeat the test.
- If the additional clamp causes additional vibration, rotate the clamps ( 1 / 4 inch above and below the mark). Repeat the vibration test.
- Increase distance between the clamp screws 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.
- If the vibration remains unacceptable, apply the same steps to the front end of the propeller shaft.
- Install the wheel and tires.
- Lower the vehicle.