Transmission speeds of compact

The invention concerns a motor vehicle gearbox, comprising at least two parallel longitudinal shafts and at least two gear assemblies comprising an idler of the first shaft geared to a stationary pinion of the second shaft, and including means for jaw clutching the idlers on their shafts via axially mobile coaxial rings, and means for controlling (10) the gear shift yokes (12) of the rings, said yokes (12) being mounted sliding longitudinally and provided with transverse legs (22) whereof the ends bear contact keys (24), transversely aligned along an arc (C), which can be received in an actuator (30) fork (36), capable of being controlled in transverse movement along the arc (C) and parallel to the shafts for selecting respectively one yoke (12), and engaging the associated ratio by displacing the yoke (12) longitudinally. The invention is characterised in that the yokes (12) are mounted sliding on a common longitudinal axle (14).