Shift Solenoid A (SSA), Shift Solenoid B (SSB), Shift Solenoid C (SSC) and Shift Solenoid D (SSD)

Shift solenoids A-D are variable force type solenoids that vary hydraulic pressure by actuating a hydraulic valve.

The PCM applies variable current to the shift solenoids which varies pressure in the hydraulic circuit to the regulator and latch valves of the clutch that it controls. Refer to HYDRAULIC CIRCUITS  for additional information.

SSA  and SSC  use proportional operation. As the current from the PCM decreases, the pressure from the solenoid decreases. As the current from the PCM increases, the pressure from the solenoid increases. SSA  and SSC  are supplied hydraulic pressure from the SOL FD circuit.

With zero current, SSA  and SSC  fully close the hydraulic valves which applies zero amount of hydraulic pressure to the clutch regulator and latch valves of the clutch that it controls and releases the clutch. With maximum current to the solenoids, the hydraulic valves are fully open for maximum pressure to the clutch regulator and latch valves to apply the clutch.

Shift Solenoid A (SSA) and Shift Solenoid C (SSC) Proportional Variable Force Type Solenoids 

Fig 1: Identifying Shift Solenoid A (SSA) And Shift Solenoid C (SSC) Proportional Variable Force Type Solenoids

Courtesy of FORD MOTOR CO.

SSB  and SSD  use inversely proportional operation. As the current from the PCM decreases, the pressure from the solenoid increases. As the current from the PCM increases, the pressure from the solenoid decreases. SSB  and SSD  are supplied hydraulic pressure from the SOL FD circuit.

With zero current, SSB  and SSD  fully open the hydraulic valves which applies maximum hydraulic pressure to the clutch regulator and latch valves to apply the clutch that it controls. With maximum current to the solenoids, the hydraulic valve is fully closed to apply zero amount of hydraulic pressure to the clutch regulator and latch valves of the clutch that it controls and releases the clutch.

Shift Solenoid B (SSB) and Shift Solenoid D (SSD) Inverse Proportional Variable Force Type Solenoids 

Fig 2: Identifying Shift Solenoid B (SSB) And Shift Solenoid D (SSD) Inverse Proportional Variable Force Type Solenoids

Courtesy of FORD MOTOR CO.