Abstract: A transmission has a drive shaft, at least two countershafts, and an output shaft. A set of gearwheels is arranged on the drive shaft, the gearwheels meshing pairwise with corresponding gearwheels on the countershafts. Gearshift sleeves provide non-rotatable interlocking of one gear wheel each of the pairs to the respective shaft on which it is provided, while the respective other gearwheel of the pair is non-rotatable interlocked to the shaft on which it is provided. Further, the countershafts each have a gearwheel meshing with a corresponding gearwheel on the output shaft. Each two gearwheels on the input shaft simultaneously mesh with one gearwheel on the first countershaft and mesh with one gearwheel on the second countershaft.

Abstract: A synchronizing mechanism for clutches comprises a gearshift sleeve provided with locking teeth coacting with locking teeth of a synchronizer ring and with separate coupling teeth coacting with the coupling teeth of clutch bodies. The locking teeth of the gearshift sleeve are provided with undercuts whose flanks exhibit substantially the same angle relative to a longitudinal axis of the teeth as the wedge surfaces formed on the ends of the coupling teeth of the clutch bodies. Once synchronism has been reached, these undercuts enable the unit formed by the clutch body and the synchronizer ring to be rotated relative to the gearshift sleeve so that the coupling teeth of the gearshift sleeve can be introduced without any resistance between the coupling teeth of the clutch body.