Abstract: A regulator valve for controlling the pressure of fluid engaging a torque-transmitting mechanism in a transmission includes a valve body forming a valve bore of a plurality of passages. A spool valve slides within the valve body. A check valve selectively opens and closes one of the passages. A spring is disposed in the valve bore and biases the spool valve in one direction. The spool valve, check valve, spring, valve bore and passages are configured to control the pressure fluid provided to the torque-transmitting mechanism and a linearly increasing pressure until a first predetermined pressure is achieved and then at a second constant predetermined pressure greater than the first predetermined pressure, thus combining gradual clutch engagement during shifting with valve boost necessary for static capacity requirements. A method of controlling engagement of the torque-transmitting mechanism is also provided.