GM Service Manual Online
For 1990-2009 cars only

Problem

Action

Throttle valve is cable out of adjustment, binding or damaged

Adjust or replace the throttle valve cable.

Throttle valve is binding or sticking

Inspect the valve body.

1-2 shift valve is binding or sticking

Inspect the valve body.

2-3 shift valve is binding or sticking

Inspect the valve body.

Primary regulator is valve binding or sticking

Inspect the valve body.

Valve springs are broken or distorted

Inspect the valve body.

Valve body casting is damaged or porous

Inspect the valve body.

Intermediate servo piston is binding or sticking

Inspect the intermediate servo piston.

Intermediate servo piston seals are cut or damaged

Inspect the intermediate servo piston seals.

Intermediate servo piston rod is binding

Inspect the intermediate servo piston rod.

2nd brake band is worn or out of alignment

Replace the 1st-reverse brake clutch discs.

1st-reverse brake clutch discs worn

Replace the 1st-reverse brake clutch.

1st-reverse brake piston or seal is leaking or damaged

Inspect the 1st-reverse brake piston.

One-way clutch not holding or damaged

Inspect the one-way clutch.