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

    Object Number: 642276 Size: SH

    Important: 

       • The flex plate 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 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 flex plate position.

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

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


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

    3. Important: A longer bolt must be used on applications using a spacer.

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

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


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

    5. 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).