Drive Pinion Flange Yoke and/or Oil Seal Replacement

Drive Pinion Flange/Yoke and/or Oil Seal Replacement

^ Tools Required
- J8614-01 Companion Flange Holder
- J23911 Pinion Oil Seal Installer
- J25273 Pinion Seal Installer

Removal Procedure
1. Remove the bolt and retainers.

Important: Observe and mark the positions of all the driveline components, relative to the propeller shaft and the axles, prior to disassembly. These components include the propeller shafts, drive axles, pinion flanges, output shafts, etc. Reassemble all the components in the exact places in which you removed the parts. Follow any specifications, torque values, and any measurements made prior to disassembly.

2. Mark the installed position of the propeller shaft and the pinion flange. Reassemble the propeller shaft and the pinion flange in the same position.





3. Remove the propeller shaft (2) from the pinion flange(3).
3.1. Use a piece of tape to hold the bearing caps.
3.2. Secure the propeller shaft up and out of the way in order to not put any stress on the universal joints.
3.3. Make an alignment mark on the pinion stem, pinion flange, and the pinion flange nut. Record the number of exposed threads on the pinion stem for reference.
3.4. Drain the axle fluid.

4. Measure the amount of torque required to turn the pinion using an inch-pound torque wrench. Record this measurement for reassembly. This will give combined pinion bearing, seal, carrier bearing, axle bearing, and seal preload.





5. Remove the pinion flange nut (1) and the washer.





6. Use J8614-01 in order to hold the pinion flange.
7. Remove the pinion flange. Place a container under the flange in order to retrieve the lubricant.
8. Remove the oil seal. Use a seal removal tool. Do not damage the carrier.
9. Inspect the seal surface of the pinion flange for tool marks, nicks, or damage, such as a groove worn by the seal. Replace the flange, if necessary.
10. Inspect the carrier bore for burrs that may cause leaks around the outside of the seal.

Installation Procedure

Important: Do not hammer the pinion flange onto the pinion stem.





1. Install a new seal using J23911.
2. Apply seal lubricant (GM P/N 1050169) to the outside of the pinion flange and the sealing lip of the new seal.
3. Install the pinion flange.

Notice: Refer to Fastener Notice in Service Precautions.

4. Install the washer and nut.
^ Tighten the nut on the pinion stem as close to the original marks as possible without going past the mark. Use the reference mark and the thread count as a reference. Tighten the nut in increments. Turn the pinion flange several times after each tightening in order to set the rollers.

Important: If the original preload torque was less than 3 inch-pounds, reset the torque specification to 3- 5 inch-pounds.





5. Measure the torque required to rotate the pinion (1). Compare this with the torque recorded earlier. Continue to tighten and measure a little at a time until the same preload is achieved.
6. Align the propeller shaft with the alignment marks made previously. Use J8614-01 in order to hold the pinion flange.
7. Install the propeller shaft to the pinion flange.
8. Install the bolts and retainers.
^ Tighten the bolts to 45 Nm (33 ft. lbs.).