Propeller Shaft Phasing Inspection
Propeller Shaft Phasing Inspection
Tools Required
J 23498-A Driveshaft Inclinometer
Inspect the propeller shaft for correct phasing. Correct phasing means that the front and the rear U-joint are directly in line or parallel with each other so that proper cancellation takes place.
1. Raise and support the vehicle. Ensure that the drive axle is supported at ride height - vehicle body supported by suspension components - with the wheels free to rotate. Refer to Lifting and Jacking the Vehicle (Service and Repair) in General Information.
2. Place the transmission in NEUTRAL.
3. Clean any corrosion or foreign material from the U-joint bearing caps.
4. Remove any of the U-joint bearing cap snap rings that may interfere with the correct placement of the J 23498-A .
5. Inspect the propeller shaft - one-piece system, or the rear propeller shaft - two-piece system, for proper phasing.
1. Rotate the propeller shaft, or shafts to align the rear shaft flanges vertically.
2. Install the J 23498-A to the lower U-joint bearing cap of the rear U-joint of the - rear - propeller shaft. The J 23498-A should be aligned perpendicular to the propeller shaft.
3. Set the indicator line on the J 23498-A to 15, the horizontal reference.
4. Rotate the propeller shaft slightly to center the bubble to the indicator. The U-joint is now vertical.
5. Without disturbing the setting on the J 23498-A , remove the J 23498-A from the rear U-joint bearing cap.
6. Install the J 23498-A to the lower U-joint bearing cap of the front U-joint of the - rear - propeller shaft.
7. Observe the reading of the front U-joint with the J 23498-A still set to 15, the horizontal reference.
6. If the difference between the front and rear U-joints of a welded-yoke propeller shaft is 3 degrees or less, the propeller shaft is properly phased.
7. If the difference between the front and rear U-joints of a welded-yoke propeller shaft is greater than 3 degrees, the propeller shaft is either constructed improperly, or damaged from twisting and it requires replacement to restore proper cancellation of the U-joints.
8. Inspect the front propeller shaft-to-slip yoke - two-piece system - for proper phasing.
1. Rotate the propeller shafts to align the front shaft and the slip yoke flanges vertically.
2. Install the J 23498-A to the lower U-joint bearing cap of the slip yoke. The J 23498-A should be aligned perpendicular to the propeller shaft.
3. Set the indicator line on the J 23498-A to 15, the horizontal reference.
4. Rotate the propeller shaft slightly to center the bubble to the indicator. The U-joint is now vertical.
5. Without disturbing the setting on the J 23498-A , remove the J 23498-A from the slip yoke U-joint bearing cap.
6. Install the J 23498-A to the lower U-joint bearing cap of the front U-joint of the front propeller shaft - two-piece system.
7. Observe the reading of the front U-joint with the J 23498-A still set to 15, the horizontal reference.
9. If the difference between the front propeller shaft U-joint and the slip yoke U-joint - two-piece system - is 3 degrees or less, the propeller shaft and the slip yoke are properly phased to each other.
10. If the difference between the front propeller shaft U-joint and the slip yoke U-joint - two-piece system - is greater than 3 degrees, the propeller shaft and the slip yoke are not aligned properly to each other at the stub shaft, constructed improperly, or damaged from twisting.
* If the stub shaft is keyed to ensure properly alignment of the front shaft and the slip yoke, then the propeller shafts require replacement to restore proper cancellation of the U-joints.
* If the stub shaft is not keyed, attempt to re-align the front shaft and slip yoke to each other. Repeat this inspection procedure to confirm the results. If proper phasing cannot be obtained, then the propeller shafts require replacement to restore proper cancellation of the U-joints.