Propeller Shaft Runout Measurement (One-Piece)

Tools Required 

• J 7872  Magnetic Base Dial Indicator Set, or equivalent
• J 8001  Dial Indicator Set, or equivalent

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 .
2. Place the transmission in NEUTRAL.
3. Clean the circumference of the propeller shaft of any debris and/or undercoating along the front (1), center (2), and rear (3) positions.
Fig 1: Identifying Propeller Shaft
Courtesy of GENERAL MOTORS CORP.
4. Inspect the propeller shaft for dents, damage, and/or missing weights. Any propeller shaft that is dented or damaged requires replacement.
5. Mount the J 7872  , or equivalent, or the J 8001  , or equivalent, to the vehicle underbody, or to a service stand in order to measure the runout of the propeller shaft beginning at the rear-most position.
   Fig 2: Measuring Propeller Shaft Runout

   Courtesy of GENERAL MOTORS CORP.
6. Rotate the pinion flange or the transmission yoke by hand while taking runout measurements of the propeller shaft. The propeller shaft will rotate more easily in one direction than in the other. If necessary, the tire and wheel assemblies and even the rotors/drums can be removed from the drive axle to provide easier rotation of the propeller shaft.

   Important:  Do not include fluctuations on the dial indicator due to welds or surface irregularities.

7. Beginning at the rear-most position and working forward, record the runout measurement at the rear (3), the center (2), and the front (1) of the propeller shaft.
   Fig 3: Identifying Propeller Shaft

   Courtesy of GENERAL MOTORS CORP.
8. Compare the propeller shaft runout measurements recorded to the runout tolerance specifications.
9. If any of the propeller shaft runout measurements exceed the runout tolerances, perform the following:
   1. Mark the position of the propeller shaft to the pinion flange.
   2. Remove the propeller shaft from the pinion flange.
   3. Rotate the propeller shaft 180 degrees from it's original position.
   4. Reinstall the propeller shaft to the pinion flange.
   5. Re-measure and record the runout of the propeller shaft at the same 3 places measured previously.
   6. Compare the propeller shaft runout measurements recorded to the runout tolerance specifications.
   7. If any of the propeller shaft runout measurements still exceed the runout tolerances, perform the following:
      1. Inspect the pinion flange runout to determine if the pinion flange is affecting the runout of the propeller shaft. Refer to Pinion Flange Runout Measurement.
      2. If the pinion flange runout exceeds the runout tolerances, the pinion flange must be re-indexed or replaced to bring the runout within tolerances before proceeding.
      3. If the pinion flange was re-indexed or replaced, return the propeller shaft to it's original relationship when reinstalling the shaft to the flange.
      4. If the pinion flange runout is within tolerances, inspect the deflection of transmission output shaft for indications of a worn or damaged bushing which could be affecting the runout of the propeller shaft. A leaking transmission output shaft seal may be an indication of an output shaft bushing concern.
      5. If the transmission output shaft bushing is found to be worn or damaged, the bushing must be replaced before proceeding.

         Important:  Inspect the runout of any replacement propeller shaft.

      6. If the first measurement of pinion flange runout was within tolerances and the transmission output shaft bushing was not found to be worn or damaged, the propeller shaft requires replacement. Check the runout of the replacement propeller shaft.
      7. If either the pinion flange was re-indexed or replaced, or if the transmission output shaft bushing was replaced; re-measure and record the runout of the propeller shaft at the same 3 places measured previously.
      8. Compare the propeller shaft runout measurements recorded to the runout tolerance specifications.
      9. If any of the propeller shaft runout measurements still exceed the runout tolerances, remove and rotate the propeller shaft 180 degrees from it's original position at the re-indexed or replaced pinion flange.
      10. Reinstall the propeller shaft to the re-indexed or replaced pinion flange then re-measure and record the runout of the propeller shaft at the same 3 places measured previously.
      11. Compare the propeller shaft runout measurements recorded to the runout tolerance specifications.

          Important:  Inspect the runout of any replacement propeller shaft.

      12. If any of the propeller shaft runout measurements still exceed the runout tolerances, the propeller shaft requires replacement. Check the runout of the replacement propeller shaft.