A transmission includes a main gear set, an auxiliary gear set and an electric motor with a rotor and a stator. A third shaft of the main gear set is connected to a transmission output shaft, and a first shaft of the auxiliary gear set is connected to the rotor. When a second shaft of the auxiliary gear set is connected to a first shaft of the main gear set, a third shaft of the auxiliary gear set is constantly connected to the third shaft of the main gear set or a fourth shaft of the main gear set. When the second shaft of the auxiliary gear set is connected to the third shaft of the main gear set, the third shaft of the auxiliary gear set is constantly connected to the fourth shaft of the main gear set.