A device (2) for a vehicle drivetrain (1) with a transmission unit (3) for changing various transmission ratios and with a hydraulic device (4). The device (2) can provide a drive torque in the area of the drive output (5) of the vehicle drivetrain (1) and in whose area a drive output torque of the vehicle drivetrain (1) can be at least partially supported. A reversing gear system (6) is connected, upstream of the transmission unit (3), for reversing the rotation direction and the hydraulic device (4) can be brought into active connection with the transmission unit (3) by way of the reversing gear system (6).