Automatic transmission for a motor vehicle, comprising an input assembly and an output assembly which are rotatably mounted about a common transmission axis, and a shift assembly by means of which the input assembly can be coupled to the output assembly, with a shift unit which is rotatably mounted about the transmission axis and coupled axially moveably and rotationally fixedly to the output assembly, wherein the shift unit has an element for force-fit coupling and a force transmission element for form-fit coupling of the input assembly and output assembly, wherein the force transmission element for form-fit coupling is arranged outside the element for force-fit coupling relative to the transmission axis, viewed in the radial direction, characterized in that the force transmission element and the element are connected via a slider which is connected to an actuating device which applies a shift force; the force transmission element is annular and has an internal toothing, and the force transmission element is rotationally fixedly coupled to the output assembly via a sliding connection arranged on the outer diameter; the element is a synchronization ring having at least two friction surfaces (10a, b); the input assembly comprises a planetary gear mechanism; a ring gear of the planetary gear mechanism is coupled to a first coupling component having a first counter-friction surface, and a planet carrier of the planetary gear mechanism is coupled to a second coupling component having a second counter-friction surface; the coupling components (19, 20) each have an external toothing (21a, 22b) which is arranged on the outer periphery and can be brought optionally into engagement with the internal toothing on the force transmission element by the axial movement of the shift unit; the coupling components (19, 20) have annular regions (17, 18), wherein counter-friction surfaces (11, 12) are arranged alternatively on internal or external ring faces of the annular regions (17, 18); and the friction surfaces (10a, 10b) of the synchronization ring can be brought into contact with the counter-friction surfaces (11, 12) of the coupling components (19, 20) by the movement of the shift unit along the sliding connection. the force transmission element for form-fit coupling is arranged outside the element for force-fit coupling relative to the transmission axis, viewed in the radial direction, characterized in that the force transmission element and the element are connected via a slider which is connected to an actuating device which applies a shift force; the force transmission element is annular and has an internal toothing, and the force transmission element is rotationally fixedly coupled to the output assembly via a sliding connection arranged on the outer diameter; the element is a synchronization ring having at least two friction surfaces (10a, b); the input assembly comprises a planetary gear mechanism; a ring gear of the planetary gear mechanism is coupled to a first coupling component having a first counter-friction surface, and a planet carrier of the planetary gear mechanism is coupled to a second coupling component having a second counter-friction surface; the coupling components (19, 20) each have an external toothing (21a, 22b) which is arranged on the outer periphery and can be brought optionally into engagement with the internal toothing on the force transmission element by the axial movement of the shift unit; the coupling components (19, 20) have annular regions (17, 18), wherein counter-friction surfaces (11, 12) are arranged alternatively on internal or external ring faces of the annular regions (17, 18); and the friction surfaces (10a, 10b) of the synchronization ring can be brought into contact with the counter-friction surfaces (11, 12) of the coupling components (19, 20) by the movement of the shift unit along the sliding connection.