GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Cooling 🢒 Valve Rocker Arm, Shaft, and Push Rod Replacement

Removal Procedure

    Object Number: 660481 Size: SH
  1. Remove the lower valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement - Lower Left Side or Valve Rocker Arm Cover Replacement - Lower Right Side .
  2. Loosen the valve clearance lock nuts on each rocker arm.
  3. Loosen the valve clearance adjusting screw on each rocker arm in order to relieve tension on the valvetrain.

    4. Object Number: 660486 Size: SH
  4. Remove the rocker arm shaft assembly bolts in the sequence shown. Leave the bolts in the rocker arm shaft brackets.

    5. Object Number: 663833 Size: SH
  5. Remove the rocker arm shaft assembly from the cylinder head.

    6. Object Number: 660488 Size: SH
  6. Remove the valve bridge pins.
  7. Remove the valve bridges.
  8. Remove the pushrods.

    9. Object Number: 667358 Size: SH
  9. Remove the rocker arm shaft bracket bolts (1), if necessary.
  10. Remove the bracket (12), rocker arm (11), and spring (10), if necessary.
  11. Remove the remaining rocker arms, springs, and brackets, if necessary.
  12. If required, clean and inspect the valve rocker arm and shaft. Refer to Valve Rocker Arm and Shaft Cleaning and Inspection .

Installation Procedure

    Object Number: 667358 Size: SH
  1. Lubricate the rocker arm shaft (7) and the inside of the rocker arms with clean engine oil, if necessary.
  2. Install the rocker arm bracket (12) and bolt (1) on one end of the rocker arm shaft, if necessary.
  3. Install the intake rocker arm (9), spring (10), exhaust rocker arm (11), and bracket (12) with bolt (1). Continue in the same sequence to the last bracket, if necessary.
  4. Push the bracket (12) to compress the springs and then install the bolt (1), if necessary.

    5. Object Number: 660488 Size: SH
  5. Lubricate the top of the valves, the valve bridge stem, the valve lifter bridge, and the valve spring caps with clean engine oil.
  6. Install the valve bridge.
  7. Install the valve bridge pins.
  8. Lubricate the valve lifter end of the pushrod with clean engine oil.
  9. Install the pushrods.

    10. To ensure the pushrod is properly installed, gently pull up on the pushrod. Resistance should be felt from the pushrod trying to lift the valve lifter.


    Object Number: 663833 Size: SH

    Notice: The pushrods must be correctly seated in the valve lifter and valve rocker arms before the rocker arm shaft assembly is torqued into place. Improper seating of the pushrods can cause damage to the pushrods or the valve rocker arm shaft assembly components.

  10. Install the rocker arm shaft assembly.

    11. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 721463 Size: SH
  11. Tighten the rocker arm shaft bolts in the sequence shown.

    12. Tighten
    Tighten the bolts to 41 N·m (30 lb ft).

  12. Adjust the valve clearance. Refer to Valve Lash Adjustment .
  13. Install the lower valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement - Lower Left Side or Valve Rocker Arm Cover Replacement - Lower Right Side .