A control system for an automatic transmission having friction coupling elements, at least one of which is locked in 3rd and 4th gears and unlocked in 1st and 2nd gears, includes a first shift valve shiftable between 3rd and 4th gears, and second shift valve shiftable between in 2nd gear and 1st gear in which engine brake available, and a solenoid valve providing control pressure which is selectively directed to these shift valves and cause them to shift so as to lock or unlock the friction coupling elements. <IMAGE>
