GM Service Manual Online
For 1990-2009 cars only

No Engine Braking in Manual Ranges Touch Activated Power

Checks

Cause

DEFINITION: A large engine RPM increase and forward vehicle speed decrease do not immediately occur when the transmission is shifted from Drive to manual ranges or a coast condition occurs in any manual range.

Accumulator and Manual 2-1 Band Servo Assembly

    â€¢ A loose or damaged manual 2-1 band servo oil pipe (125)
    â€¢ Loose manual 2-1 band servo cover or accumulator cover bolts (103, 131)
    â€¢ A damaged accumulator cover spacer plate assembly (134)
    â€¢ A damaged or missing servo piston seal (107) or a servo piston cylinder O-ring seal (113)
    â€¢ A missing servo exhaust screen assembly (115), allowing debris into the cylinder
    â€¢ A misassembled manual 2-1 servo assembly (103-115)

Manual 2-1 Band Assembly

    â€¢ A band assembly (680) that is worn or burned
    â€¢ A band assembly (680) that is disengaged from the anchor pin (102)
    â€¢ A band anchor pin (102) that is loose or missing

Low Regulator Valve

Valve stuck or missing spring

1-2 Shift Solenoid

Valve stuck OFF