Abstract: A rotary switch, used to select the operating range of an automatic transmission, controls solenoid-operated valves corresponding to the selected range. The valves open and close a connection between a range valve and control pressure source. The range valve includes two spools having three positions. The spools are biased apart by a compression spring located between the spools. One valve position opens the fluid pressure source to a line that is pressurized to produce forward drive, a second position opens a connection between the fluid pressure source and a line that is pressurized to produce reverse drive, and a third position vents those lines to sump. The spring locates the spools at the third position. Control pressure force on opposite ends of each spool forces both spools to the first and second positions in response to the range selected by the vehicle operator.

Abstract: An electronically controlled multiply ratio transmission for an automotive vehicle powertrain having a hydrokinetic torque converter with a bypass clutch, solenoid operated shift valves under the control of an electronic microprocessor that receives signals from an output shaft speed sensor, an engine speed sensor, a driver controlled drive range selector position, an engine throttle position sensor, and other powertrain operating variables, the bypass clutch having a controlled slip characteristic.

Abstract: An electrically controlled multiple ratio transmission for an automotive vehicle powertrain having a hydrokinetic torque converter with a bypass clutch, solenoid operated shift valves under the control of an electronic microprocessor that receives signals from an output shaft speed sensor, an engine speed sensor, a driver controlled drive range selector position, an engine throttle position sensor, and other powertrain operating variables, the solenoid shift valves forming a part of a simplified control valve circuit having a minimum number of shift valve elements and simplified circuit pressure modifier elements for effecting optimum pressures in fluid pressure operated servos for the transmission clutches and brakes during ratio changes, the bypass clutch having a controlled slip characteristic.

Abstract: A multiple ratio automotive vehicle transmission having a hydrokinetic torque converter and a compound planetary gear unit that establish a plurality of underdrive ratios, a direct drive ratio and an overdrive ratio, the ratio changes from the first underdrive ratio to a second underdrive ratio from the second underdrive ratio to the direct drive ratio each being established by engagement by a single torque establishing device, brake means for controlling application and release of the torque establishing devices to effect transmission of reaction torque from a reaction element of the gearing to a stationary portion of the mechanism, said controlling means being adapted to establish optimum shift points during ratio changes regardless of the magnitude of the torque being delivered at the instant a ratio shift occurs.

Abstract: An automatic power transmission control system having a throttle valve adapted to be connected mechanically through a linkage to the adjustable engine carburetor throttle valve in an automotive vehicle driveline wherein provision is made, in the event of a failure of a mechanical linkage, for an increase in the effective throttle pressure signal made available to the control valve elements of the transmission system thereby assuring that the transmission clutches and brakes will have sufficient control pressure to maintain torque transmitting capacity for both torque delivery to the traction wheels as well as during engine braking of the vehicle at high speeds.

Abstract: A fluid pressure governor adapted to sense the driven speed of an automatic transmission torque output shaft and to develop a speed signal that may be used by an automatic transmission control circuit in conjunction with a torque demand or engine torque signal to control automatic ratio changes in a transmission mechanism as torque is delivered from a vehicle engine to vehicle traction wheels. Provision is made for interrupting the speed signal distribution to the control elements of the transmission mechanism when deceleration of the vehicle exceeds a critical value thus causing the transmission mechanism to downshift to higher torque ratios during rapid deceleration of the vehicle and thereby eliminating any tendency of the vehicle engine to stall or to malfunction as a result of braking of the vehicle.