A friction brake for a vehicle power shift transmission is disclosed. The friction brake includes a load gear that is rotatably driveable about a centre longitudinal. A friction braking device is provided for decelerating and/or fixing the load gear. An actuating device for actuating the friction braking device, the actuating device includes an moveable spreading piston. The moveable spreading piston while performing a spread along the centre longitudinal axis automatically materialising as a function of a load torque provided on the load gear, provides a braking force for actuating the friction braking device.