An actuator (1) for an automated or automatic transmission has a cylinder housing (3), a piston unit (2), and a piston rod (13). The piston unit (2) is coupled to the piston rod (13) and is arranged movably in the cylinder housing (3) along a longitudinal axis (4). The piston unit (2) separates two pressure chambers (8, 9) of variable volume in the cylinder housing (3). The pressure chambers are configured to load the piston unit (2) with compressed air on both sides. The two pressure chambers (8, 9) are connected to a valve unit (14) for switching between pressurization and purging of each of the two pressure chambers (8, 9). An end stop clamping device for damping at least one end stop of the piston unit (2) is arranged in the actuator (1). A pneumatically and a mechanically operating damping stage are provided improve the end stop damping device.