Abstract: A hydraulic control device operates a sliding selector shaft, in particular a gearbox for motor vehicles, with a bore made in a wall of a gearbox housing for accommodating a plastic piston. The piston is actively connected to the sliding selector shaft and delimits a pressure chamber and, under hydraulic pressure, radially guides and axially displaces the sliding selector shaft. The piston has a body and a guide section consisting of plastic. The piston is guided directly at the bore, designed as a non-reinforced and unlined cylinder bore, in the wall of the gearbox housing, consisting of a light metal alloy. This creates control device, which is of a much simpler, and more compact design compared with prior art.