Speed switching drive for motor vehicles

The speed-change gearbox comprises several gear sets equipped with synchronized clutches and switchable driving gears such as forward gears and one reverse gear. The change speed transmission (10) is divided into two partial transmissions (I,II) by switching unit (26,38) such as clutch. The partial transmissions are decoupled in response to predetermined one gear change unit driving gear and/or as a function of defined switching states of the switching unit.