GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC Sierra Denali 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, and 6.0L 🢒 Engine Flywheel Replacement

Removal Procedure

    Object Number: 178458 Size: SH
  1. Remove the automatic transmission, if equipped. Refer to Transmission Replacement in Automatic Transmission - 4L60-E or Transmission Replacement in Automatic Transmission - 4L80-E.

    2. Important: Note the position and direction of the engine flywheel before removal.

  2. Remove the engine flywheel bolts.
  3. Remove the automatic transmission engine flywheel, if applicable.

    4. Object Number: 156166 Size: SH
  4. Remove the clutch, if equipped with a manual transmission. Refer to Clutch Assembly Replacement in Clutch.

    5. Important: Note the position and direction of the engine flywheel before removal.

  5. Remove the engine flywheel bolts.
  6. Remove the manual transmission engine flywheel, if applicable.
  7. If required, clean and inspect the engine flywheel. Refer to Engine Flywheel Cleaning and Inspection .

    8. Object Number: 642281 Size: SH
  8. Install two M11x1.5 mm bolts (1) to the threaded holes of the spacer, if applicable.
  9. Rotate the bolts clockwise to remove the spacer.

    10. Object Number: 642276 Size: SH
  10. Remove the spacer from the rear of the crankshaft, if applicable.

Installation Procedure

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 three stage tightening process.
   • Certain applications (4.8 L manual transmissions or all 6.0 L) require a spacer and longer bolts for proper flywheel position.


    Object Number: 642276 Size: SH
  1. Install the spacer (if applicable) onto the rear of the crankshaft.

    2. 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 engine flywheel to the crankshaft, if applicable.

    4. Important: Longer flywheel bolts must be used on applications using a flywheel spacer.

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

    5. Object Number: 63174 Size: SH

    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.

  5. Install the engine flywheel bolts.

    6. Tighten

    1. Tighten the bolts a first pass in sequence to 20 N·m (15 lb ft).
    2. Tighten the bolts a second pass in sequence to 50 N·m (37 lb ft).
    3. Tighten the bolts a final pass in sequence to 100 N·m (74 lb ft).
  6. Install the clutch, if equipped with a manual transmission. Refer to Clutch Assembly Replacement in Clutch.
  7. Install the automatic transmission, if equipped. Refer to Transmission Replacement in Automatic Transmission - 4L60-E or Transmission Replacement in Automatic Transmission - 4L80-E.