GM Service Manual Online
For 1990-2009 cars only

Check

Causes

DEFINITION: A large engine RPM increase and forward vehicle speed decrease do not immediately occur when the transmission is shifted from third to fourth gear in Drive or Manual Third range to either second gear or Manual Second.

Coast Clutch

    • Damaged or cut piston
    • Damaged or worn clutch plates
    • Damaged or stuck ball check valve
    • 3-4 shift valve and/or 3-4 control shift valve stuck released
    • Low pressure control valve stuck released
    • 4-5 shift valve and/or 4-5 control shift valve stuck released
    • 1-2 shift valve stuck applied
    • 2-3 shift and/or 2-3 control shift stuck released