GM Service Manual Online
For 1990-2009 cars only

Checks

Causes

1-2 Shift Solenoid Valve

    • Debris, or failed OFF
    • Pinched or damaged wires, inoperative

1-2 Shift Valve

Stuck in upshifted position

Checkball No. 8

Missing

Checkballs

Missing from FWD/coast clutch

Forward Clutch Piston

Damaged or cracked

Forward Clutch Piston Seals

Rolled, cut or damaged

Forward Sprag

Damaged, not holding

FWD/CC Studs

Damaged, broken

FWD/CC Support Seals

Damaged

Lo/Rev Servo Apply Pin

Apply pin damage

Lo Roller Clutch

Worn or damaged

Support Housing Seal Rings

Leaking, damaged or cut