A control apparatus in an automatic transmission includes first and second shift valves which are independently actuable to define four distinct states corresponding to four speed ranges of the transmission. In the first state, neither valve participates in achieving the first range. In the second state, only the first valve participates in achieving the second range. In the third state, only the second valve participates in achieving the third range. In the fourth state, both valves participate in locking a lock-up clutch by being fluidly interconnected by an interconnecting passage so as to define a signal pressure passage which conducts a signal pressure to a lock-up relay valve to implement a locking of the lock-up clutch.