GM Service Manual Online
For 1990-2009 cars only

Manual First Gear With Touch Activated Power

A manual 2-1 downshift is initiated by moving the gear selector lever to the Manual position. However, the transmission will not downshift into First gear until vehicle speed is below approximately 60 km/h (37 mph). At higher vehicle speeds the PCM will keep 1-2 shift solenoid (SS) valve de-energized (OFF) and the transmission will operate in Manual -- Second Gear. Also, the third clutch is applied in Manual First -- First Gear to provide engine compression braking.

Manual Valve (404)

Line pressure is routed into the braking circuit when the selector lever is moved into the Manual position. Line pressure continues to feed the D4 in Manual.

Number 7 Ball Check Valve (372)

Located in the control valve body (300), directs braking to the 1-2 shift valve (318).

1-2 Shift Valve (318)

When shifted against spring force, allows braking to enter the braking-1st gear passage to the low regulator valve (313). During release of the 2nd clutch, exhausting 2nd fluid passes through the valve and enters the 3rd fluid passage.

Lo Blow Valve (443)

When shifted against spring force, allows braking first gear fluid to be directed into low reg fluid passage.

Number 4 Ball Check Valve (372)

Located in the case cover (400), it seats against 3rd clutch fluid allowing low reg fluid to enter the 3rd clutch/lo-1st fluid passage and apply the 3rd clutch.

1-2, 3-4 Shift Solenoid (SS) Valve (315)

Energizes, allowing line pressure to feed into the 1-2, 3-4 signal fluid passage and to the 3-4 shift valve (362).

Number 2 Ball Check Valve (372)

Located in the case cover (400), forces exhausting 2nd clutch apply fluid through an orifice into the 2nd clutch passage and to the 1-2 shift valve (318).

Drive Range, Manual 1st - from Drive, Manual 2nd - With Touch Activated Power


Object Number: 1174586  Size: FS
Control Valve Body Fluid Passages (Case Cover Side)
Control Valve Body Fluid Passages (Case Cover Side)
Control Valve Body Fluid Passages (Case Cover Side)
Control Valve Body Fluid Passages (Case Cover Side)
Control Valve Body Fluid Passages (Case Cover Side)
Control Valve Body Fluid Passages (Case Cover Side)
Case Cover Fluid Passages (Control Valve Body Side)
Case Cover Fluid Passages (Control Valve Body Side)
Case Cover Fluid Passages (Control Valve Body Side)
Case Cover Fluid Passages (Control Valve Body Side)