2001 GMC C3500 HD 6.5 F, AutomaticFACTORY OEM SERVICE PROCEDURE

Removal Procedure

    CAUTION: Refer to Battery Disconnect Caution in Cautions and Notices.
  1. Remove the negative battery cables.
  2. Remove the intake manifold. Refer to Intake Manifold Removal- Upper and Intake Manifold Removal - Lower in Engine Mechanical - 6.5L.
  3. Remove the injection lines. Refer to Fuel Injection Line(s) Replacement .
  4. Remove the fuel inlet line from the injection pump.
  5. Remove all necessary harness connectors and hoses from the injection pump.
  6. Remove the fuel return line at the top of the injection pump.
  7. Remove the oil fill tube.
  8. Remove the grommet for the oil filler tube.
    9. Fig 1: Driven Gear-To-Injection Pump Bolt
    GM27614Courtesy of GENERAL MOTORS CORP.
  9. Rotate the engine to gain access to the bolts (1) that hold the driven gear to the injection pump. Access is gained through the oil filler neck hole.
  10. Remove the driven gear bolts.
    IMPORTANT: Never engage the starter motor to rotate the engine when the injection pump is removed as severe engine damage will occur. With the injection pump removed the pump driven gear could jam in the front housing by engaging the starter motor, resulting in a sheared crankshaft or camshaft gear key and possible valve train damage. Always bar the engine over by hand to avoid internal engine damage.
    11. Fig 2: Injection Pump Flange Nuts
    GM193160Courtesy of GENERAL MOTORS CORP.
  11. Remove the injection pump flange nuts. Use the J 41089  injection pump wrench. See Special Tools .
    12. Fig 3: Injection Pump
    GM193162Courtesy of GENERAL MOTORS CORP.
  12. Remove the injection pump.
  13. Cap all open lines and nozzles.
  14. Remove the flange gasket.
Factory Service Tools

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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.