Abstract: A hydraulic control for a power transmission has a regulator valve for controlling the hydraulic system pressure and a plurality of shift valves for controlling the automatic ratio change in the transmission. The shift valves are urged toward the higher ratio position by a governor pressure. The shift valves, except the 1-2 valve, are selectively subjected to separate modulated throttle valve pressures acting in opposition to the governor pressure and depending upon whether the respective shift valve is in the lower or higher ratio position. The modulated pressures are maintained at substantially zero for a portion of the throttle valve pressure range so that upshifting and downshifting will be sensitive to governor pressure and therefore vehicle speed only.The regulator valve is subject to a variable bias pressure which is proportional to throttle valve pressure.

Abstract: A manually operable locking mechanism for an automatic transmission has a pawl which engages a toothed member connected to the transmission output shaft. The pawl is controlled for engagement and disengagement with the toothed member through a manually operated cam which moves a lock lever toward the engaged position. The lock lever, through a tension spring, urges a lock strut to enforce engagement of the pawl. On manual disengagement, the cam contacts and moves the lock strut to relieve the locking force from the pawl thus permitting disengagement of the pawl and the toothed member. The lock lever abuts the cam after disengagement to establish the relative positions of the cam, lock lever and lock strut when the disengage position is selected.