The invention relates to an electro-pneumatic switch unit for a motor vehicle gear transmission comprising a main driving gear, a splitting change-gear transmission which is pneumatically switchable through a valve and an electronic control device (8). A valve (14, 14') is actuated by a reverse speed shifting, and the pressure transmitted to the cylinder (6) of the splitting change-gear transmission is released by an electric valve (12) in order to switch said transmission in such a way that the piston (17) of the cylinder (6) pushes a corresponding gearshift fork by means of a control rod (19) in an opposite direction with respect to a sliding coupling (5) for synchronising the splitting change-gear transmission, thereby producing a braking torque which slows the wheelset thereof in such a way that the reverse gear can be shifted without rattle. |