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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 455 (ENGINE MECHANICAL)REPAIR INSTRUCTIONSOFF-VEHICLE REPAIR INSTRUCTIONSPISTON AND CONNECTING ROD ASSEMBLETOOLS REQUIRED
1999 GMC Forward Control 5.7 R, Automatic

Tools Required

1999 GMC Forward Control 5.7 R, AutomaticSECTION Tools Required
WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

J 24086-C  Piston Pin Remover and Installer Set

Important:  Assemble the piston for the specific cylinder with the connecting rod for the corresponding crankshaft journal.

  1. Install the fork insert J 24086-310 into fixture J 24086-10. 
    Fig 1: Installing Fork Insert J 24086-310 Into Fixture J 24086-10
    G01500736Courtesy of GENERAL MOTORS CORP.
  2. Lubricate the piston pin with clean engine oil.

    Important:  Ensure that the marks on the piston and connecting rod are aligned the same as when removed. If installing a new piston, ensure that the arrow on top faces towards the front of the engine. If no identification marks were made during disassembly, ensure that the flat area on the bottom of the piston pin skirt is aligned with the small dimple above the connecting rod crankshaft bearing bore.

  3. Assemble the piston, connecting rod and adapter J 24086-6A and install onto fixture J 24086-10. 
    Fig 2: Assembling Piston, Connecting Rod And Adapter J 24086-6A
    G01500737Courtesy of GENERAL MOTORS CORP.
  4. Adjust installation pin J 24086-9  to G-4.
    Fig 3: Identifying Installation Pin J 24086-9
    G01500738Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.