Automatic transmission control system

A multiple ratio geared transmission adapted to deliver torque from a throttle controlled internal combustion engine to a driven shaft in an automotive vehicle driveline comprising a transmission pump driven by said engine and multiple ratio gear elements forming multiple torque flow paths between said engine and said driven shaft;

• clutch means for establishing and disestablishing said torque flow paths and brake means for establishing and disestablishing torque reaction points for said torque flow paths;
• multiple fluid pressure operated servo means including clutch servo means and brake servo means for respectively actuating said clutch means and said brake means;
• a fluid control valve circuit including said pump, first shift valve means in said circuit for controlling pressure distribution from said pump selectively to a first of said servo means to effect a first transmission ratio, second shift valve means in said circuit for controlling pressure distribution to a second of said servo means to effect a second transmission ratio and a third shift valve means in said circuit for controlling pressure distribution to a third of said servo means;
• said first and second shift valve means comprising movable valve elements located in a common valve bore, one valve element in said common bore being engageable with the other valve element in said common bore whereby shifting movement of one valve element in one direction results requires said other valve element to be moved in said one direction;
• multiple shift solenoid valve means in said circuit having on and off operating states, electronic processor means for controlling changes in said operating states;
• said valve circuit including shift signal pressure passages extending from said shift solenoid valve means to one end of said one valve element and to one end of said other valve element whereby actuating forces are developed on said one valve element and said other valve element.