Express, Savana, G1500, G2500, G3500, 1998-2005

Pinion Seal

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Removal & Installation



  1. Raise the vehicle.
  2.  
  3. Remove the tire and wheel assemblies.
  4.  
  5. Remove the rear brake calipers and rotors or drums.
  6.  
  7. Remove the axle shafts on 10.5 inch and 11.5 inch axles.
  8.  
  9. Reference mark the rear propeller shaft to the rear axle pinion yoke.
  10.  
  11. Disconnect the propeller shaft from the axle.
  12.  
  13. Measure the torque required to turn the pinion. Record the torque number measurement which gives the combined pinion bearing, seal, carrier bearing, axle bearing and seal preload.
  14.  
  15. Make and accurate alignment mark on the pinion flange. Record the number of exposed threads on the pinion stem.
  16.  
  17. Remove the pinion flange nut and the washer. Use a container in order to catch any lubricant.
    NOTE
    Use care not to damage any of the machined surfaces.

  18.  
  19. Remove the pinion flange.
    NOTE
    The pinion flange has an oil seal that is part of the pinion flange assembly. The pinion flange must be inspected to ensure that the seal is not damaged.

  20.  
  21. Pry the oil seal from the bore.
  22.  
  23. Thoroughly clean any foreign material from the contact area. Replace any parts as necessary.

    Click image to see an enlarged view

    Fig. Measuring the turning torque of the pinion

  24.  

To install:

  1. Lubricate the cavity between the lips of the oil seal with wheel bearing lubricant.
  2.  
  3. Install the oil seal into the bore using a driver.
    NOTE
    Do not hammer the pinion flange onto the pinion stem.

  4.  
  5. Install the pinion flange. Use the alignment marks in the installation of the pinion flange.
  6.  
  7. Install the washer and a new nut. Tighten the nut on the pinion stem as close as possible to the alignment marks without going past the marks. Use the alignment marks and the thread count as a reference. Tighten the nut a little at a time. Turn the pinion flange several times after each tightening in order to seat the rollers.
  8.  
  9. Measure the torque required to rotate the pinion flange. Compare this to the original torque. Tighten the pinion nut, in small increments, until the rotating torque is 3 inch lbs. (0.35 Nm) GREATER than the original torque.
  10.  
  11. Align the propeller shaft with the alignment marks. Connect the propeller shaft.
  12.  
  13. Install the axle shafts on 10.5 inch and 11.5 inch axle.
  14.  
  15. Install the rear brake calipers and rotors or drums.
  16.  
  17. Install the tire and wheel assemblies.
  18.  

Full Floating Axles
  1. Raise and support the truck on jackstands. It would help to have the front end slightly higher than the rear to avoid fluid loss.
  2.  
  3. Matchmark and remove the driveshaft.
  4.  
  5. Matchmark the pinion shaft, nut and flange. Count the number of exposed threads on the pinion shaft.
  6.  
  7. Install a holding tool on the pinion. A very large adjustable wrench will do, or, if one is not available, set the parking brake as tightly as possible.
  8.  
  9. Remove the pinion nut.
  10.  
  11. Slide the flange off of the pinion. A puller may be necessary.
  12.  
  13. Centerpunch the oil seal to distort it and pry it out of the bore. Be careful to avoid scratching the bore.
  14.  

To install:

  1. Pack the cavity between the lips of the seal with lithium-based chassis lube.
  2.  
  3. Position the seal in the bore and carefully drive it into place. A seal installer is VERY helpful in doing this.
  4.  
  5. Place the flange on the pinion and push it on as far as it will go.
    WARNING
    Never hammer the flange into place!

  6.  
  7. Install the pinion washer and nut on the shaft and force the pinion into place by turning the nut.
  8.  
  9. On models with the 11 inch ring gear, tighten the nut to 440-500 ft. lbs. (596-678 Nm)
  10.  
  11. On models with the 10 1 / 2 inch ring gear Tighten the nut until the exact number of threads previously noted appear and the matchmarks align.
  12.  
  13. Install the driveshaft.
  14.  

Semi-Floating Axles
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Raise and support the truck on jackstands. It would help to have the front end slightly higher than the rear to avoid fluid loss.
  4.  
  5. Matchmark and remove the driveshaft.
  6.  
  7. Release the parking brake.
  8.  
  9. Remove the rear wheels. Rotate the rear wheels by hand to make sure that there is absolutely no brake drag. If there is brake drag, remove the drums.
  10.  
  11. Using a torque wrench on the pinion nut, record the force needed to rotate the pinion.
  12.  
  13. Matchmark the pinion shaft, nut and flange. Count the number of exposed threads on the pinion shaft.
  14.  
  15. Install a holding tool on the pinion. A very large adjustable wrench will do, or, if one is not available, put the drums back on and set the parking brake as tightly as possible.
  16.  
  17. Remove the pinion nut.
  18.  
  19. Slide the flange off of the pinion. A puller may be necessary.
  20.  
  21. Centerpunch the oil seal to distort it and pry it out of the bore. Be careful to avoid scratching the bore.
  22.  

To install:

  1. Pack the cavity between the lips of the seal with lithium-based chassis lube.
  2.  
  3. Position the seal in the bore and carefully drive it into place. A seal installer is VERY helpful in doing this.
  4.  
  5. Pack the cavity between the end of the pinion splines and the pinion flange with Permatex® No.2 sealer, or equivalent non-hardening sealer.
  6.  
  7. Place the flange on the pinion and push it on as far as it will go.
  8.  
  9. Install the pinion washer and nut on the shaft and force the pinion into place by turning the nut.
    WARNING
    Never hammer the flange into place!

  10.  
  11. Tighten the nut until the exact number of threads previously noted appear and the matchmarks align.
  12.  
  13. Measure the rotating torque of the pinion under the same circumstances as before. Compare the two readings. As necessary, tighten the pinion nut in VERY small increments until the torque necessary to rotate the pinion is 3 inch lbs. (0.35 Nm) higher than the originally recorded torque.
  14.  
  15. Install the driveshaft.
  16.  

 
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