GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39946 Crankshaft Rotation Socket

Removal Procedure

  1. Remove the oil pump. Refer to Oil Pump Replacement .

  2. Object Number: 517185  Size: SH
  3. Align the primary timing marks (1) using the J 39946 .
  4. Remove the secondary camshaft drive chains. Refer to Secondary Camshaft Drive Chain Replacement - Right Side and Secondary Camshaft Drive Chain Replacement - Left Side .
  5. Remove the primary drive chain tensioner. Refer to Primary Camshaft Drive Chain Tensioner Replacement .

  6. Object Number: 534270  Size: SH
  7. Remove the camshaft intermediate sprocket retaining bolt (3).
  8. Remove the following as an assembly:
  9. • The primary camshaft drive chain (4)
    • The crankshaft sprocket
    • The camshaft intermediate sprocket
  10. Clean and inspect the camshaft timing drive components. Refer to Camshaft Timing Drive Components Cleaning and Inspection .

Installation Procedure


    Object Number: 207540  Size: SH
  1. Align the timing marks (1) of the camshaft intermediate and crankshaft sprockets. The marks should be aligned vertically in the installed position.
  2. Install the primary camshaft drive chain on the drive sprockets.
  3. Make sure that the number 1 piston is at top dead center (TDC) and the crankshaft keyway is approximately at the 1 o'clock position.

  4. Object Number: 534270  Size: SH
  5. Use the J 39946 to align the crankshaft key (1) with the drive sprocket.
  6. Install the following as an assembly:
  7. • The primary camshaft drive chain (4)
    • The crankshaft sprocket
    • The camshaft intermediate sprocket

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  8. Install the camshaft intermediate sprocket retaining bolt (3).
  9. Tighten
    Tighten the camshaft intermediate sprocket retaining bolt to 60 N·m (44 lb ft).

    Important: DO NOT remove the pin holding the tensioner until the secondary timing chains are installed.

  10. Install the primary drive chain tensioner. Refer to Primary Camshaft Drive Chain Tensioner Replacement .
  11. Install the secondary camshaft drive chains. Refer to Secondary Camshaft Drive Chain Replacement - Left Side and Secondary Camshaft Drive Chain Replacement - Right Side .
  12. Remove the pin from the primary timing chain tensioner release lever.

  13. Object Number: 517185  Size: SH
  14. Ensure the primary timing marks (1) are aligned vertically.
  15. Install the oil pump. Refer to Oil Pump Replacement .