Abstract: Systems and methods for actuating engine valves are disclosed. The systems may include primary and auxiliary rocker arms disposed adjacent to each other on a rocker arm shaft. A rocker arm coupling assembly may be disposed between the auxiliary rocker arm and the primary rocker arm. The coupling assembly may include a piston having a curved surface disposed in a bore formed in the primary rocker arm, and a slot having a second radius of curvature formed in the auxiliary rocker arm. The piston may be selectively hydraulically locked into an extended position between the primary and auxiliary rocker arms so as to selectively transfer one or more auxiliary valve actuation motions from the auxiliary rocker arm to the primary rocker arm.