In an auxiliary range transmission comprising a main group having a main transmission shaft and two main countershafts capable of rotating in relation to two auxiliary countershafts of a range or an auxiliary transmission group, a gearshift element is provided, which, in a first position, rotationally engages a loose gear of the main group and, in a second position, rotationally locks a loose gear of the range or auxiliary group with the main shaft. In an alternative embodiment, a splitter group may also be arranged in front of the main group in place of the range or auxiliary transmission group.