GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C-Series Medium Duty Truck B7 🢒 Engine 🢒 Engine Mechanical - 8.1L 🢒 Crankshaft Balancer Replacement

Tools Required

    • J 24420-C Harmonic Balancer Puller
    • J 42845 Crankshaft Balancer Installer
    • J 42847 Flywheel Holding Tool

Removal Procedure

    Object Number: 470799 Size: SH
  1. Remove the fan shroud. Refer to Fan Shroud Replacement in Engine Cooling.
  2. Remove the drive belt. Refer to Drive Belt Replacement .
  3. Raise and suitably support the vehicle with safety stands. Refer to Lifting and Jacking the Vehicle in General Information.
  4. Remove the starter motor. Refer to Starter Motor Replacement in Engine Electrical.

    5. 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.

    Important: Make sure the teeth of the flywheel holding tool engage the engine flywheel teeth.

  5. Install the J 42847 to the starter bolt holes.

    6. Tighten
    Tighten the J 42847 bolts to 50 N·m (37 lb ft).


    Object Number: 677814 Size: SH
  6. Install the J 24420-C or equivalent onto the crankshaft balancer.
  7. Tighten the center screw of the J 24420-C until the crankshaft balancer is clear of the crankshaft nose.
  8. Remove the crankshaft balancer.
  9. Clean and inspect the crankshaft balancer. Refer to Crankshaft Balancer Cleaning and Inspection in the Engine Unit Repair Manual.

Installation Procedure

Important: 

   • The balancer should be positioned onto the end of the crankshaft as straight as possible prior to tool installation.
   • Apply grease or clean engine oil to the crankshaft balancer or the end of the crankshaft to prevent galling during assembly.


    Object Number: 639539 Size: SH
  1. Install the balancer onto the end of the crankshaft.
  2. Install the J 42845 to the crankshaft balancer.

    3. Important: Apply the lubricant that comes with J 42845 each time the tool is used. Failure to lubricate J 42845 may prevent the balancer from installing completely.

  3. Using J 42845 install the balancer.
  4. Tighten the J 42845 until the crankshaft balancer is completely seated against the crankshaft sprocket.

    5. Object Number: 639542 Size: SH
  5. Remove the J 42845 from the crankshaft balancer.

    6. Object Number: 470799 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.

  6. Install the crankshaft balancer bolt and washer.

    7. Tighten
    Tighten the crankshaft balancer bolt to 225 N·m (189 lb ft).

  7. Remove the J 42847 .
  8. Install the starter. Refer to Starter Motor Replacement in Engine Electrical.
  9. Install the drive belt. Refer to Drive Belt Replacement .
  10. Install the fan shroud. Refer to Fan Shroud Replacement in Engine Cooling.