GM Service Manual Online
For 1990-2009 cars only

No 3-4 Shift

Checks

Cause

Control Valve Assembly

    â€¢ Stuck 3-4 shift valve
    â€¢ Stuck 4-3 manual downshift valve

Fourth Clutch Shaft

Damaged spline

Fourth Clutch Assembly

    â€¢ Burned clutch plates
    â€¢ Damaged piston or seals
    â€¢ Mislocated clutch plates or piston

Shift Cable

Adjust the shift cable