GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 Sierra Denali 🢒 Transmission 🢒 Automatic Transmission - Allison 🢒 Oil Pump Inspection

    Object Number: 1645507 Size: SH

    Important: 

       • Make the following measurements described below at several locations.
       • Replace the oil pump body, driven gear and drive gear if any of the following specifications are not met.

  1. Measure the depth of the oil pump body gear cavity at dimension A.

    2. Specification
    The gear cavity maximum depth is 22.245 mm (0.8758 in).


    Object Number: 1645509 Size: SH
  2. Measure the ID of the oil pump body gear cavity at dimension A.

    3. Specification
    The gear cavity maximum ID is 110.191 mm (4.3382 in).


    Object Number: 1587643 Size: SH
  3. Measure the OD of the driven gear at dimension A.

    4. Specification
    The driven gear minimum OD is 109.987 mm (4.3302 in).


    Object Number: 1587644 Size: SH
  4. Measure the distance between the flats of the drive gear at dimension A.

    5. Specification
    The maximum distance between the flats is 52.165 mm (2.0537 in).


    Object Number: 1587645 Size: SH
  5. Align the drive gear (1) and driven gear (2) with the oil pump so that their punch marks are in the same position as when they were originally removed.
  6. Install the gears into the oil pump body (3).

    7. Object Number: 1587646 Size: SH
  7. Measure the clearance between the driven gear (1) and the oil pump body (2), driven gear diametrical clearance.

    8. Specification
    The driven gear maximum diametrical clearance is 0.20 mm (0.0080 in).


    Object Number: 1587649 Size: SH
  8. Measure the clearance between the driven gear (1) and the oil pump body crescent (2).

    9. Specification
    The driven gear/crescent maximum clearance is 0.455 mm (0.0179 in).


    Object Number: 1587650 Size: SH
  9. Hold a straight edge across the oil pump body (1) and the drive gear (3). Measure the clearance between the drive gear and the straight edge. This is the drive gear side clearance.

    10. Specification
    The drive gear maximum side clearance is 0.066 mm (0.0026 in).

  10. Hold a straight edge across the oil pump body (1) and the driven gear (2). Measure the clearance between the driven gear and the straight edge.

    11. Specification
    The driven gear maximum side clearance is 0.056 mm (0.0022 in).


    Object Number: 1587645 Size: SH
  11. Remove the drive gear (1) and driven gear (2) from the oil pump body (3).

Oil Pump Wear Plate Inspection

    Object Number: 1423502 Size: SH

    Important: Replace the oil pump wear plate if specifications are not met.

  1. Inspect the wear plate (1) for damage. The wear plate must not be scored, nicked, or grooved.
  2. Measure the thickness of the wear plate in the gear wear area.

    3. Specification
    The thickness of the wear plate must not be less than 2.950 mm (0.116 in).