GM Service Manual Online
For 1990-2009 cars only

Checks

Causes

Oil Pump (4)

    • Damaged vanes
    • Missing slide spring
    • Oil pump screen assembly plugged or damaged
    • Oil pump rotor guide omitted or misassembled
    • Oil pump rotor cracked or broken
    • Porosity in fluid pump
    • Oil pump surfaces not flat
    • Excessive oil pump rotor clearance

Forward Sprag Clutch Assembly (642)

    • Damaged sprag
    • Worn or pitted inner race

Input (662) and Reaction (681) Carrier

Damaged or worn gears