GM Service Manual Online
For 1990-2009 cars only

Engine Flywheel Installation 5.3L


    Object Number: 1401955  Size: SH

    Important: The flex plate does not use a locating pin for alignment and will not initially seat against the crankshaft flange, but will be pulled onto the crankshaft by the engine flex plate bolts. This procedure requires a 3 stage tightening process.

  1. Install the flex plate to the crankshaft.
  2. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489), or equivalent, to the threads of the flex plate bolts.
  3. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 63174  Size: SH
  4. Install the engine flex plate bolts.
  5. Tighten

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

Engine Flywheel Installation 6.0L


    Object Number: 1401955  Size: SH

    Important: The flywheel and flex plate do not use a locating pin for alignment and will not initially seat against the crankshaft flange, but will be pulled onto the crankshaft by the bolts. This procedure requires a 3-stage tightening process.

  1. Install the automatic transmission flex plate to the crankshaft, if applicable.

  2. Object Number: 1199288  Size: SH
  3. Install the manual transmission flywheel to the crankshaft, if applicable.
  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
  6. Install the engine flywheel bolts (1-6).
  7. Tighten

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