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 suitably 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 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), the rear propeller shaft (two-piece system), or the front and rear propeller shafts (three-piece system) for proper phasing.

5.1.	Rotate the propeller shaft(s) to align the shaft flanges vertically.

5.2.	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.

5.3.	Set the indicator line on the J 23498-A to 15, (the horizontal reference).

5.4.	Rotate the propeller shaft slightly to center the bubble to the indicator. The U-joint is now vertical.

5.5.	Without disturbing the setting on the J 23498-A , remove the J 23498-A from the rear U-joint bearing cap.

5.6.	Install the J 23498-A to the lower U-joint bearing cap of the front U-joint of the (rear) propeller shaft.

5.7.	Observe the reading of the front U-joint with the J 23498-A still set to 15 (the horizontal reference).

5.8.	For three-piece systems, install the J 23498-A to the lower U-joint bearing cap of the rear U-joint of the front propeller shaft.

5.9.	Without disturbing the setting on the J 23498-A , remove the J 23498-A from the rear U-joint bearing cap.

5.10.

Install the J 23498-A to the lower U-joint bearing cap of the front U-joint of the front propeller shaft.

5.11.

Observe the reading of the front U-joint with the J 23498-A still set to 15 (the horizontal reference).

6. For three-piece systems, inspect the center (intermediate) propeller shaft for proper phasing.

6.1.	Rotate the propeller shafts 1/4 turn.

6.2.	Install the J 23498-A to the lower U-joint bearing cap of the rear U-joint of the center propeller shaft.

6.3.	Without disturbing the setting on the J 23498-A , remove the J 23498-A from the rear U-joint bearing cap.

6.4.	Install the J 23498-A to the lower U-joint bearing cap of the front U-joint of the center propeller shaft.

6.5.	Observe the reading of the front U-joint with the J 23498-A still set to 15 (the horizontal reference).

7. Inspect the front-to-rear propeller shafts (two-piece system) for proper phasing.

7.1.	Rotate the propeller shafts to align the rear shaft flanges vertically.

7.2.	Install the J 23498-A to the lower U-joint bearing cap of the front U-joint of the rear propeller shaft. The J 23498-A should be aligned perpendicular to the propeller shaft.

7.3.	Set the indicator line on the J 23498-A to 15, (the horizontal reference).

7.4.	Rotate the propeller shaft slightly to center the bubble to the indicator. The U-joint is now vertical.

7.5.	Without disturbing the setting on the J 23498-A , remove the J 23498-A from the front U-joint bearing cap.

7.6.	Install the J 23498-A to the lower U-joint bearing cap of the U-joint of the transmission output shaft yoke (two-piece system).

7.7.	Observe the reading of the front U-joint with the J 23498-A still set to 15 (the horizontal reference).

8. 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.
9. 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.
10. If the difference between the transmission output shaft yoke U-joint and the front U-joints of the rear propeller shaft (two-piece system) is 3 degrees or less, the propeller shafts are properly phased to each other.
11. If the difference between the transmission output shaft yoke U-joint and the front U-joints of the rear propeller shaft (two-piece system) is greater than 3 degrees, the propeller shafts 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 and rear shafts, 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 and rear shafts 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.

12. If the difference between the front and rear U-joints of a slip-yoke propeller shaft (three-piece system) is 3 degrees or less, the propeller shaft is properly phased.
13. If the difference between the front and rear U-joints of a slip-yoke propeller shaft (three-piece system) is greater than 3 degrees, the propeller shaft and its 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 propeller shaft and the yoke, then the propeller shaft assembly requires replacement to restore proper cancellation of the U-joints.

•	If the stub shaft is not keyed, attempt to re-align the propeller shaft and the yoke to each other. Repeat this inspection procedure to confirm the results. If proper phasing cannot be obtained, then the propeller shaft assembly requires replacement to restore proper cancellation of the U-joints.