GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Crankshaft Reluctor and Oil Pump Drive Gear Replacement

Removal Procedure

    Object Number: 738905 Size: SH
  1. Remove the engine front cover. Refer to Engine Front Cover Replacement.

    2. Caution: Do not use an impact driver to remove or install the oil pump driven gear nut. Use of an impact driver may shear the oil pump drive gear pin in the crankshaft.

  2. While holding the secondary oil pump shaft with a hex driver, remove the oil pump driven gear nut.
  3. Remove the oil pump driven gear.

    4. Object Number: 738904 Size: SH
  4. Remove the oil pump drive gear and crankshaft sensor reluctor. Do not damage the crankshaft reluctor teeth.

    5. Object Number: 739296 Size: SH

    Note: Do not remove the reluctor from the oil pump drive gear unless replacing the reluctor or the oil pump drive gear. The reluctor is timed to the gear and once removed the correct timing will be lost.

  5. Remove the crankshaft reluctor to oil pump drive gear bolts.
  6. Inspect the crankshaft reluctor for the damage, bent teeth, being bent or warped.
  7. Inspect the oil pump drive gear for damaged or worn teeth.
  8. Inspect the oil pump drive gear crankshaft pin for wear.
  9. Inspect the groove of the crankshaft pin in the oil pump drive gear for wear.
  10. Replace any parts that are damaged or worn.

Installation Procedure

    Object Number: 739295 Size: SH

    Note: The crankshaft reluctor and the oil pump drive gear are timed at the factory. In order to re-establish proper timing, install knock pins in the oil pump drive gear if the crankshaft reluctor was removed from the oil pump drive gear. The knock pins are available through the parts department.

  1. Install the knock pins in the oil pump drive gear to a height of 4.5-5.5 mm (0.177-0.217 in)

    2. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 739296 Size: SH
  2. Install the crankshaft reluctor on the oil pump drive gear. Ensure the reluctor is aligned on the knock pins.
  3. Install the crankshaft reluctor bolts.

    4. Tighten
    Tighten the bolts to 8 N·m (71 lb in).


    Object Number: 738904 Size: SH

    Note: Do not damage the teeth on the crankshaft reluctor.

  4. Install the oil pump drive gear and reluctor to the crankshaft.

    5. Object Number: 738905 Size: SH
  5. Install the oil pump driven gear.

    6. Caution: Do not use an impact driver to remove or install the oil pump driven gear nut. Use of an impact driver may shear the oil pump drive gear pin in the crankshaft.

  6. While holding the secondary oil pump shaft with a hex driver, install the oil pump driven gear nut.

    7. Tighten
    Tighten the nut to 100 N·m (74 lb ft).

  7. Install the engine front cover. Refer to Engine Front Cover Replacement.