GM Service Manual Online
For 1990-2009 cars only

Checks

Causes

Oil Pump (4)

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

Forward Sprag Clutch Assembly (642)

    â€¢ Damaged sprag
    â€¢ Worn or pitted inner race

Input (662) and Reaction (681) Carrier

Damaged or worn gears