Transmission unit for a motor vehicle, having a manual transmission and an electric machine, wherein the manual transmission has one single input shaft which can be coupled to a main drive of the motor vehicle, and one single output shaft which can be coupled to an output of the motor vehicle, wherein the connection of the electric machine to the manual transmission is carried out via an idler gear pack which comprises: - a first input shaft idler gear arranged on the input shaft, a second input shaft idler gear which has a first gearwheel and a second gearwheel with a different-sized diameter and a first double-speed manual transmission by means of which in a first active position the first input shaft idler gear can be connected non-rotationally to the input shaft and in a second active position the second input shaft idler gear can be connected non-rotationally to the input shaft, - a first output shaft idler gear arranged on the output shaft, a second output shaft idler gear which has a first gearwheel and a second gearwheel having a differently-sized diameter, wherein the first input shaft idler gear meshes directly with the first gearwheel of the second output shaft idler gear, the first output shaft idler gear meshes directly with the first gearwheel of the second input shaft idler gear, and wherein the second gearwheel of the second input shaft idler gear meshes directly with the second gearwheel of the second output shaft idler gear, characterised in that the idler gear pack comprises a second double-speed manual transmission by means of which in a first active position the second output shaft idler gear can be connected non-rotationally to the output shaft and in a second active position the first output shaft idler gear can be connected non-rotationally to the output shaft. - a first input shaft idler gear arranged on the input shaft, a second input shaft idler gear which has a first gearwheel and a second gearwheel with a different-sized diameter and a first double-speed manual transmission by means of which in a first active position the first input shaft idler gear can be connected non-rotationally to the input shaft and in a second active position the second input shaft idler gear can be connected non-rotationally to the input shaft, - a first output shaft idler gear arranged on the output shaft, a second output shaft idler gear which has a first gearwheel and a second gearwheel having a differently-sized diameter, wherein the first input shaft idler gear meshes directly with the first gearwheel of the second output shaft idler gear, the first output shaft idler gear meshes directly with the first gearwheel of the second input shaft idler gear, and wherein the second gearwheel of the second input shaft idler gear meshes directly with the second gearwheel of the second output shaft idler gear, characterised in that the idler gear pack comprises a second double-speed manual transmission by means of which in a first active position the second output shaft idler gear can be connected non-rotationally to the output shaft and in a second active position the first output shaft idler gear can be connected non-rotationally to the output shaft.