GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2006 🢒 GMC Sierra Denali 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, and 6.0L 🢒 Engine Flywheel Installation

    Object Number: 642276 Size: SH

    Important: 

       • The flywheel does not use a locating pin for alignment, and will not initially seat against the crankshaft flange or spacer, if applicable, but will be pulled onto the crankshaft by the engine flywheel bolts. This procedure requires a 3 stage tightening process.
       • Certain applications, the 4.8L manual transmission and all 6.0L, require a spacer and longer bolts for proper flywheel position.

  1. Install the spacer, if applicable, onto the rear of the crankshaft.

    2. A longer flywheel bolt must be used on applications using a flywheel spacer.


    Object Number: 156166 Size: SH
  2. Install the manual transmission engine flywheel to the crankshaft, if applicable.

    3. Object Number: 178458 Size: SH
  3. Install the automatic transmission flex plate to the crankshaft, if applicable.

    4. Important: A longer flex plate bolt must be used on applications using a flex plate spacer.

  4. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489), or equivalent, to the threads of the bolts.

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


    Object Number: 63174 Size: SH
  5. Install the bolts.

    6. Tighten

    1. Tighten the bolts (1-6) a first pass in sequence to 20 N·m (15 lb ft).
    2. Tighten the bolts (1-6) a second pass in sequence to 50 N·m (37 lb ft).
    3. Tighten the bolts (1-6) a final pass in sequence to 100 N·m (74 lb ft).