A drive engages a shaft (4) and, via at least one shaft (5, 6) of a transmission, an electric machine. An output can be connected to another shaft (9). During gear shifts, the shafts (4, 5, 6, 9) are couple such that the rotational speed of the shaft (5, 6), which can couple the electric machine when torque at the shaft (9) is equivalent to the torque of the electric machine, and is a product of the gear ratio between the shaft (5, 6) and the shaft (9) and the rotational speed of the shaft (9) or, when torque present at the shaft (9), is equal to the torque of the drive engine or electric machine, and is a sum of the product of the rotational speed of the shaft (4) and a first variable, and the product of the rotational speed of the shaft (9) and a second variable.