A parallel shift transmission of a motor vehicle comprising splitter and range groups. At least the splitter group is split into two parallel transmission branches having countershafts. One branch can be actuated by a power-shift element to transfer rotation of a drive shaft to a countershaft, via a stepped transmission ratio of the splitter group according to the actuation of one of the transmission branches and then converting and transmitting the rotation, via one of a plurality of range transmission ratios of the range group, to an output shaft. In order to reverse rotation, parallel countershafts can be coupled by individual gearwheel pairs by actuation of associated switching elements such that one countershaft, at the output side of the splitter group in the flow of power flow from the drive to the output shaft, is connected to the other countershaft at a drive side of the range group.