The invention relates to a positively engaging shifting element which can be hydraulically or pneumatically actuated, comprising a hydraulically or pneumatically actuatable piston (I) having a piston compartment (2) containing a hydraulic medium or pressure medium, a pressure medium supply (6) for the piston (I), a jaw (3) and a mating jaw (4) with which the jaw (3) meshes when engaged. The engaging speed of the jaw (3) can be increased by decoupling the jaw (3) from the hydraulic or pneumatic volume flow when the jaws (3) and (4) are in a tooth butt position in relation to each other and by pretensioning the jaw (3) by means of a hydraulic or pneumatic pressure reservoir (7) that is actively connected to the piston (I) and that is connected to the pressure medium supply (6). The gap between the jaws, i.e. the window into which the jaw (3) can be engaged is maintained as narrow as possible in order for a tooth butt position of the jaws (3) and (4) in relation to each other being highly probable when the shift element is applied.