GM Service Manual Online
For 1990-2009 cars only

No Engine Braking; All Manual Ranges

Checks

Causes

Coast Clutch

No apply or slipping

Piston and Seal Assembly (504)

Binding, cracked, or leaking

Clutch Plates (508, 509)

Worn friction or broken splines

Springs (505)

Binding

Direct & Coast Clutch Housing and Input Shaft (502)

    • Damaged or cracked
    • Fluid feed holes are restricted

Housing Retainer and Ball Assembly

Missing or loose

Coast Clutch Fluid Routing

Fluid leak or restriction

    • Valve Body Gaskets and Spacer Plate
    • Channel Plate and Gasket
    • Driven Sprocket Support
    • Porosity
    • Misalignment
    • Looseness
    • Fluid restriction
    • Fluid leak across the channels

Driven Sprocket Support Seals

Leaking

Input Shaft (502)

    • Leaking seals
    • Damaged or misaligned sleeve

Oil Level or Line Pressure

Low Pressure (Refer to High or Low Line Pressure )

3-4 Shift Valve (319)

Stuck in Fourth gear position (No coast clutch apply)

Manual Valve or Shift Linkage (800)

Misaligned