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Bob
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
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Submitted: 9 years ago.
Category: Chevy
Expert:  Bob replied 9 years ago.

You need to use a dial type torque wrench when taking it loose and see how much torque is required to turn the pinion, so you know how much to put on it going back together. If it is already off, the only proper way to re install it is to replace the pinion bearing crush sleeve and set the rear end up all over again.

Document ID# XXXXX
1999 Chevrolet Astro - 2WD

 

Drive Pinion Flange/Yoke and/or Oil Seal Replacement


Tools Required

J 8614-01 Pinion Flange Holder
J 23911 Pinion Oil Seal Installer
J 33782 Pinion Oil Seal Installer
Removal Procedure

    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. Assemble all the components in the exact places in which you removed the parts. Follow any specifications, torque values, and measurements made prior to disassembly.

  1. Raise the vehicle.
  2. Remove the tire and wheel assemblies.
  3. Remove the brake drums.
  4. Remove the propeller shaft.
    Object Number: 791776  Size: MH

  5. Determine the type of pinion oil seal used:
    - 2 lip pinion seal -- This seal type can be identified by the short deflector (1) used on the pinion yoke/flange.
    - 3 lip pinion seal -- This seal type can be identified by the long deflector (2) used on the pinion yoke/flange.

    Object Number: 661077  Size: SH

  6. Measure the amount of torque required to rotate the pinion. Use an inch-pound torque wrench. This will give the combined preload for the following components:
    - The pinion bearings
    - The pinion seal
    - The carrier bearings
    - The axle bearings
    - The axle seals
  7. Record the measurement.
    Object Number: 788905  Size: SH

  8. Draw an alignment mark between the pinion stem and the pinion flange/yoke.
    Object Number: 661080  Size: SH

  9. Install the J 8614-01 as shown.
  10. Remove the pinion nut while holding the J 8614-01 .
  11. Remove the washer.
    Object Number: 661074  Size: SH

  12. Install the J 8614-2 (2) and the J 8614-3 (3) into the J 8614-01 (1) as shown.
  13. Remove the pinion yoke by turning the J 8614-3 (3) clockwise while holding the J 8614-01 (1). Use a container in order to retrieve the lubricant.

    Important: Do not damage the axle housing sealing surface.

  14. Remove the pinion oil seal using a suitable seal removal tool.

Installation Procedure


    Object Number: 651744  Size: SH

    Important: When replacing the pinion oil seal and/or the pinion flange/yoke, observe the following guidelines:

    When replacing only the pinion oil seal, the same style pinion oil seal must be used as the one that was removed.
    If replacing both the pinion oil seal and the pinion flange/yoke, the same style of pinion oil seal and the pinion flange/yoke must be used.
    The 2 lip and the 3 lip style pinion oil seals and pinion flange/yokes are not interchangeable.

     

  1. Install the new pinion gear oil seal. For the 2 lip style pinion oil seal, use the J 23911 . For the 3 lip style pinion oil seal, use the J 33782 .
  2. Apply sealant, GM P/N 12346004 or equivalent, to the splines of the pinion flange/yoke.

    Important: Install the pinion gear flange/yoke to the pinion gear shaft in the same position as marked during removal in order to maintain correct driveline balance.

  3. Install the pinion flange/yoke. Align the marks made during removal.

    Notice: Do not hammer the pinion flange/yoke onto the pinion shaft. Pinion components may be damaged if the pinion flange/yoke is hammered onto the pinion shaft.

  4. Seat the pinion flange/yoke onto the pinion shaft by tapping it with a soft-faced hammer until a few pinion shaft threads show through the yoke.
  5. Install the washer and a new pinion nut.
    Object Number: 661080  Size: SH

  6. Install the J 8614-01 onto the pinion flange/yoke as shown.

    Important: If the rotating torque is exceeded, the pinion will have to be removed and a new collapsible spacer installed.

  7. Tighten the pinion nut while holding the J 8614-01 .

    Tighten
    Tighten the nut until the pinion end play is removed. Rotate the pinion while tightening the nut to seat the bearings.


    Object Number: 661077  Size: SH

  8. Measure the rotating torque of the pinion. Compare this measurement with the rotating torque recorded during removal.

    Tighten
    Tighten the nut in small increments, as needed, until the rotating torque is 0.40-0.57 N·m (3-5 lb in) greater than the rotating torque recorded during removal.

  9. Once the specified torque is obtained, rotate the pinion several times to ensure the bearings have seated. Check the rotating torque and adjust if necessary.
  10. Install the propeller shaft.
  11. Install the brake drums.
  12. Install the tire and wheel assemblies.
  13. Inspect and add axle lubricant to the axle housing, if necessary.
  14. Lower the vehicle.

Document ID# XXXXX
1999 Chevrolet Astro - 2WD

Customer: replied 9 years ago.
Reply to Bob's Post: is there no absolute torque number for the pinion nut, the pinion seal is leaking I can't trust using the reverse torque #
Expert:  Bob replied 9 years ago.
Hi, Hate to say it but there is no dried and cut number that I can give you as GM won't specify one. Best bet is to count the threads showing on the pinion flange, turn the flange back and forth to get a feel for how tight it is and then use the reverse torque readings as a back up. When you out it back together, just count the threads, but be critical on that part as that will put you close. Then use the torque wrench and see how close it feels to the way it felt before. he concern is with getting it too tight and messing up the pinion bearing or the crush sleeve. Wish there was a magic number I could give you, but it would be a lie. Goo luck with it.
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