•  Fluid under pressure from the pump flows to several hydraulic controls in the valve body, including the main regulator valve. The main regulator valve varies line pressure as part of controlling shift feel and efficient apply component operation.

•  The TCM controls the position of the main regulator valve with the pressure control solenoid A and B.

•  When pressure control solenoid A and B pressures are lower, the main regulator valve position provides lower line pressure. As the fluid pressures from pressure control solenoid A and B increase, the main regulator valve provides higher line pressure.

•  When the transmission shifter is in the R position, fluid under pressure from the manual valve to the apply components also affects the position of the main regulator valve. This results in a pressure boost.

•  In the 5R55S transmission, pressure control solenoid A affects the operation of the main regulator valve and the VFS1 modulator control valve.

•  VFS1 pressure indirectly affects the feel of the forward clutch engagement. VFS1 pressure is directly applied to the intermediate servo. It is also directly applied to the low/reverse servo in manual 1GR and manual 2GR.

•  In the 5R55S transmission, pressure control solenoid B affects the operation of the main regulator valve, the VFS2 modulator control valve, the forward engagement control valve and the reverse engagement control valve.

•  VFS2 pressure indirectly affects the feel of the forward clutch engagement, as well as the direct clutch engagement in reverse. VFS2 pressure is directly applied to the overdrive servo or the coast clutch.

•  In the 5R55S transmission, pressure control solenoid C solenoid affects the operation of the reverse pressure modulator valve and the reverse engagement control valve.

•  Pressure control solenoid C pressure indirectly affects the feel of direct clutch engagement in reverse. Pressure control solenoid C pressure is directly applied to the direct clutch in 4GR and 5GR.