Solenoid Hydraulic Circuits

WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

LINE pressure from the pump is directed to the individual shift, TCC and LPC solenoids by the solenoid regulator valve on the SOL FEED circuit. The solenoids, controlled by the PCM, direct the fluid to the valves that they control.

The LPC solenoid sends varying pressure to the line pressure regulator valve to control line pressure.

In PARK position, Shift Solenoid D (SSD) directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit. Shift Solenoid E (SSE) directs pressure to the multiplex shift valve to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch.

Fig 1: Identifying Park Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In REVERSE position, SSD directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit. SSE directs pressure to the multiplex shift valve to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch. Shift Solenoid B (SSB) directs pressure to the direct (3, 5, R) regulator and boost valves through the SSB SIG hydraulic circuit to apply the direct (3, 5, R) clutch.

Fig 2: Identifying Reverse Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In NEUTRAL position, SSD directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit. SSE directs pressure to the multiplex shift valve to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch.

Fig 3: Identifying Neutral Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In 1st gear, Shift Solenoid A (SSA) directs pressure to the forward (1, 2, 3, 4) clutch regulator and boost valves through the SSA SIG hydraulic circuit to apply the forward (1, 2, 3, 4) clutch. SSD directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit only when vehicle speed is below 5 km/h (3 mph). SSE directs pressure to the multiplex shift valve to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch only when vehicle speed is below 5 km/h (3 mph).

Fig 4: Identifying 1st Gear Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In 2nd gear, the forward (1, 2, 3, 4) clutch remains applied. Shift Solenoid C (SSC) directs pressure to the intermediate (2, 6) clutch regulator valve through the SSC SIG hydraulic circuit to apply the intermediate (2, 6) clutch.

Fig 5: Identifying 2nd Gear Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In 3rd gear, the forward (1, 2, 3, 4) clutch remains applied. SSC releases pressure to the intermediate (2, 6) clutch regulator valve. SSB directs pressure to the direct (3, 5, R) regulator and boost valves through the SSB SIG hydraulic circuit to apply the direct (3, 5, R) clutch.

Fig 6: Identifying 3rd Gear Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In 4th gear, the forward (1, 2, 3, 4) clutch remains applied. SSB releases pressure to the direct (3, 5, R) regulator and boost valves. SSD directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit to apply the overdrive (4, 5, 6) clutch.

Fig 7: Identifying 4th Gear Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In 5th gear, the overdrive (4, 5, 6) clutch remains applied. SSA releases pressure to the forward (1, 2, 3, 4) regulator and boost valves. SSB directs pressure to the direct (3, 5, R) regulator and boost valves through the SSB SIG hydraulic circuit to apply the direct (3, 5, R) clutch.

Fig 8: Identifying 5th Gear Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.

In 6th gear, the overdrive (4, 5, 6) clutch remains applied. SSB releases pressure to the direct (3, 5, R) regulator and boost valves. SSC directs pressure to the intermediate (2, 6) clutch regulator valve through the SSC SIG hydraulic circuit to apply the intermediate (2, 6) clutch.

Fig 9: Identifying 6th Gear Position Solenoid Hydraulic Circuits

Courtesy of FORD MOTOR CO.