GM Service Manual Online
For 1990-2009 cars only

Harsh Shifts

Check

Causes

DEFINITION: Harsh shift feel - an unacceptable quick gear change occurs.

Pressure Control Solenoid

    • Damaged O-rings
    • Contamination

Output Speed Sensor

Open or grounded circuit

Input Speed Sensor

Open or grounded circuit

Throttle Position

Open or grounded circuit

Forward Clutch Assembly

    • Damaged or worn clutch plates
    • Damaged or cut piston
    • Damaged or stuck ball check valve

Control Valve Body Accumulator Assembly

    • Accumulator piston stuck
    • Stuck or missing ball check valves

Fluid Pump

    • Pressure regulator valve stuck
    • Pressure regulator valve spring
    • Line boost valve spring
    • Line boost valve or bushing stuck, damaged or incorrectly assembled
    • Fluid pump screen assembly plugged or damaged
    • Fluid pump rotor guide omitted or misassembled
    • Fluid pump rotor cracked or broken
    • Porosity in fluid pump
    • Fluid pump surfaces not flat
    • Excessive fluid pump rotor clearance
    • Pump slide seal out of location
    • Pump vanes damaged
    • Pump slide spring damaged

Inspect for active transmission DTCs

Transmission DTC default action active