For 1990-2009 cars

Before making a shift from fourth to fifth range, the transmission control module (TCM) makes certain all of the shift valves are in the correct position with shift valves C and E down and shift valve D up.

Shift solenoid B is de-energized, exhausting B trim valve signal pressure and the B trim valve moves up, which allows the 1-2-3-4 clutch to exhaust through the manual valve, shift valves E and C and the B trim valve. Pressure control solenoid A is de-energized, raising the A trim signal and A trim pressures. The A trim pressure is directed through shift valve D to the 3rd, 5th, and Reverse clutch, applying the clutch. The TCM reduces the current to the pressure control solenoid A, which controls the rate at which trim valve A supplies pressure to the 3rd, 5th, and Reverse clutch, and reduces the current to the pressure control solenoid B, which controls the rate at which trim valve B exhausts the 1-2-3-4 clutch, assuring a smooth transition from fourth to fifth range. The 4-5 clutch continues to be applied by main pressure flowing through shift valve E, shift valve D and the manual valve.

The combination of the 4-5 clutch and the 3rd, 5th, and Reverse clutch application produces fifth range operation.

After the shift to fifth range is complete, shift solenoid C is de-energized, removing control main pressure from the top of shift valve C, causing the valve to move up and removing control main pressure from switch C. After the TCM has confirmed that shift valve C has moved up, and pressure switch C is turned off, shift solenoid B is energized, directing pressure through shift valves E and D to the overdrive knockdown port of the main pressure regulator valve. Overdrive knockdown reduces regulated main pressure. This function is calibration dependent and may not be active for all applications.

Pressure switches C and D are turned off, providing feedback that the C and D shift valves are in the up position, and pressure switch E remains on, providing feedback that shift valve E is in the down position.

If electrical power is interrupted with the transmission in fifth range, the pressure control solenoid B, shift solenoid E, and the torque converter clutch pulse width modulated (TCC PWM) solenoid, if the TCC is applied, de-energize. Although shift solenoid E no longer supplies control main pressure to the top of shift valve E, control main pressure flows through shift valve C to the top of shift valve E, keeping the valve down. The pressure from the B trim valve is exhausted, removing pressure from the overdrive knockdown circuit, allowing main pressure to regulate at a higher pressure. Normally closed pressure control solenoid A continues to block the exhaust of the solenoid signal pressure, and the solenoid signal remains control main. The solenoid signal pressure on top of trim valve A produces maximum trim pressure, which is routed through shift valve D to the 3rd, 5th, and Reverse clutch, keeping the clutch applied. Main pressure feeds through shift valves E and D and the manual valve to the 4-5 clutch, keeping the clutch applied. The combination of the 4-5 clutch and the 3rd, 5th, and Reverse clutch application produces fifth range operation for limp home capability. If the TCC is applied, the TCC PWM solenoid de-energizes, causing the F trim valve to move up, exhausting pressure from the top of the converter flow valve. The converter flow valve moves up, redirecting main overage to converter in and converter out flow to the cooler. The TCC is now released.

If electrical power is interrupted with the transmission in fifth range, causing fifth range converter operation, and the manual valve is moved to Neutral (N), the 4-5 clutch exhausts through the manual valve to exhaust backfill, releasing the 4-5 clutch. The 3rd, 5th, and Reverse clutch remains applied. With only one clutch applied, the transmission goes to Neutral (N).

If electrical power is interrupted with the transmission in fifth range, causing fifth range converter operation, and the manual valve is moved to Reverse (R), the 4-5 clutch exhausts through the manual valve, releasing the clutch. The 3rd, 5th, and Reverse clutch remains applied. With only one clutch applied, the transmission goes to Neutral (N).

If electrical power is interrupted with the transmission in fifth range, resulting in only fifth and Neutral (N) operation, the engine may be shut down and restarted to attain Neutral (N), third and Reverse (R) operation.

#### Fifth Range Hydraulic Schematic