Abstract: A system for controlling a pump in a hydraulic circuit for an automatic transmission, having a viscosity insensitive fixed orifice and a relatively high resistance laminar orifice connected in series relationship between a vent port and a control pressure supplied to a secondary regulated pressure SRP valve. At relatively low temperature, flow through the laminar orifice is negligible; therefore, the steady-state differential pressure across the fixed orifice is negligible. At relatively higher temperatures, flow through the laminar orifice increases. A pressure divider is established and the feedback differential pressure is reduced in proportion to the hydraulic resistance of the two orifices. Flow to friction elements from a primary pump and auxiliary pump and return of fluid to the inlets of the pumps is controlled through a clutch capacity pressure regulator valve acting in cooperation with the SRP valve.

Abstract: A system for controlling operation of a bypass clutch for a torque converter in an automatic transmission includes a converter lockout valve for producing a pressure signal having a first magnitude indicating unlocked operation of the converter clutch and a second magnitude representing locked operation, the pressure magnitudes being produced in response to control pressures representing engine speed, transmission operation in any forward gear, and in a first forward gear.

Abstract: An automatic transmission having a hydraulic torque converter and a multiple-ratio gear system in an automotive vehicle driveline wherein the converter includes a pressure-actuated bypass clutch and a control valve system for maintaining a regulated charge pressure in the torque converter and for controlling the actuation and release of the bypass clutch, the valve system including a main regulator that establishes a circuit pressure and that establishes priority distribution of pressurized fluid to the torque converter while temporarily interrupting distribution of pressurized fluid to the transmission lubrication circuit.