Differential Pinion Input Shaft Runout Measurement

Differential Pinion Input Shaft Runout Measurement

Tools Required

J 7872 - Magnetic Base Dial Indicator Set, or equivalent

Important:
This measurement procedure is intended to measure drive axle pinion input shaft runout for systems with a constant velocity (CV) joint, rubber coupling or bolt-on U-joint yoke at the drive axle.


1. Place the transmission in NEUTRAL.

2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle Service and Repair.

3. If equipped with a CV joint, measure the drive axle pinion input shaft radial runout on the splined surface of the prop shaft rear CV joint housing, as close to the flange as possible:

1. Clean the surface of the prop shaft rear CV joint housing just ahead of the torque tube input flange.

2. Mount a J 7872 - magnetic base dial indicator set, or equivalent and position the dial indicator to contact the prop shaft rear CV joint housing as close to the drive axle input flange as possible.

4. If equipped with a rubber coupling or bolt-on U-joint yoke, measure the differential pinion input shaft radial runout on the machined surface of the flange pilot area:

1. Mark the position of the prop shaft to the drive axle input flange.

2. Separate the propshaft from the drive axle input flange.

3. Clean the surface of the flange pilot area.

4. Mount a J 7872 - magnetic base dial indicator set, or equivalent and position the dial indicator to contact the pilot area as close to the drive axle input flange as possible.

5. If equipped with a torque tube, measure the radial runout on the machined surface of the splined shaft:

1. Remove the torque tube assembly from the vehicle.

2. Clean the surface of the splined shaft.

3. Mount a J 7872 - magnetic base dial indicator set, or equivalent and position the dial indicator to contact the machined area as close to the end of the shaft as possible.

6. Rotate the drive axle input shaft by hand to locate the low spot.

7. Set the dial indicator to zero on the low spot.

8. Rotate the shaft by hand and record the amount of radial runout.

9. Compare the runout of the shaft to the runout tolerance specifications guidelines.

10. If the drive axle input shaft runout exceeds the specification, the flange requires replacement.