Manual First Gear. Cadillac Concours 1997

For 1990-2009 cars

When the gear selector lever is moved to the Manual First (1) gear range, the manual valve moves and allows line pressure to enter the Low fluid passage. If the vehicle is operating below 56 km/h (35 mph), the transmission will shift immediately into first gear. the transmission is prevented from upshifting. During the shift into Manual First gear, the following changes occur within the transmission:

### Low & Reverse Band Applies

#### Manual Valve

Line pressure at the manual valve enters the Low fluid circuit. Line pressure is then routed to checkball #8.

#### #8 Checkball (Low)

Low fluid pressure unseats the #8 checkball, which is located in the valve body. This pressure then routes Low fluid to the 2-3 shift valve.

#### 2-3 Shift Valve

Spring force hold the 2-3 shift valve in the downshifted position. Low fluid passes through the valve and Low fluid enters the Low feed circuit. Low feed passes through orifice #4, and Low feed enters the orificed Low feed circuit. Low feed is then routed to the 1-2 shift valve.

#### 1-2 Shift Solenoid (SS) Valve

When the PCM energizes (turns ON) the 1-2 SS valve, high fluid pressure from the 1-2 SS valve builds at the end of the 1-2 shift valve. This causes the valve to downshift against spring force.

#### 1-2 Shift Valve

Fluid pressure from the 1-2 SS valve holds the 1-2 shift valve in the downshifted position. The valve allows orificed Low feed to pass through the valve and enter the Low & Reverse band reduce circuit. Low & Reverse band reduce is then routed to checkball #6 and to the spring side of the Low & Reverse servo piston.

#### #6 Checkball (Low Reverse Band Apply and Reduce)

The #6 checkball is located in the valve body. The checkball is unseated by Low & Reverse reduce fluid. This allows fluid to enter the Low & Reverse band apply circuit. Low & Reverse band apply fluid is then routed to the Low & Reverse servo piston where the fluid actuates the piston and applies the Low & Reverse band assembly.

### Fourth Band Releases

#### 1-2 Shift Valve

High fluid pressure from the 1-2 shift solenoid (SS) valve holds the 1-2 shift valve in the downshifted position. The valve allows fourth band fluid from the fourth servo and from the 3-4 accumulator piston to pass through the valve. Fourth band fluid then enters an exhaust passage where the fluid is routed through orifice #2 before exiting the circuit.

### Second Clutch Releases

#### 1-2 Shift Valve

High 1-2 solenoid fluid pressure holds the 1-2 shift valve in the downshifted position. The valve allows second clutch fluid from the second clutch piston and from the 1-2 accumulator piston to pass through the valve and to exhaust.

#### Manual First Gear

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)