GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 35621-B Rear Main Seal Installer

Removal Procedure


    Object Number: 31379  Size: SH
  1. Remove the flywheel. Refer to Engine Flywheel Replacement .
  2. Insert a flat-tipped screwdriver into the access notches and carefully pry the seal from the housing.
  3. Discard the seal.
  4. Clean off any dirt or rust in the area.

Installation Procedure


    Object Number: 334550  Size: SH
  1. Apply 2 to 3 drops of clean engine oil to the bore of the housing.
  2. Apply 2 to 3 drops of clean engine oil to the outside diameter of the engine flywheel pilot flange.
  3. Apply 1 drop of clean engine oil to the outside diameter of the flywheel locator pin.
  4. Apply 2 to 3 drops of clean engine oil to the crankshaft seal surface.

  5. Object Number: 1700105  Size: SH

    Important: Notice the direction of the rear oil seal. The new design seal is a reverse style as opposed to what has been used in the past. THIS SIDE OUT has been stamped into the seal as shown in the graphic.

  6. Inspect the J 35621-B flange for imperfections that may damage the NEW seal.
  7. Minor imperfections may be removed with a fine grade emery cloth.

    Important: DO NOT allow oil or any other lubricants to contact the seal lip surface of the seal.

  8. Remove the sleeve from the seal.
  9. Apply 2 to 3 drops of clean engine oil to the outside diameter of the seal.
  10. Install the seal onto the J 35621-B .
  11. Install the J 35621-B onto the rear of the crankshaft and hand tighten the tool bolts until snug.
  12. Notice: Proper alignment of the crankshaft rear oil seal is critical. Install the crankshaft rear oil seal near to flush and square to the crankshaft rear oil seal housing. Failing to do so may cause the crankshaft rear oil seal or the crankshaft rear oil seal installation tool to fail.

  13. Install the seal onto the crankshaft and into the housing:
  14. 10.1. Turn the J 35621-B wing nut clockwise until the seal is installed close to flush and square to the housing.

    Increased resistance will be felt when the seal has reached the bottom of the housing bore.

    10.2. Turn the J 35621-B wing nut counterclockwise to release the J 35621-B from the seal.
  15. Remove the J 35621-B .
  16. Wipe off any excess engine oil with a clean rag.
  17. Install the engine flywheel. Refer to Engine Flywheel Replacement .