Gearbox for motor vehicles

A gearbox (1) for a motor vehicle and configured to be connected to an output side of a basic gearbox, said gearbox (1) comprising:

• an input shaft (2) from the basic gearbox, an output shaft (3) to a transmission, and a planetary gear (4) arranged between the input shaft (2) and the output shaft (3);
• the ring gear (18) of the planetary gear (4) is axially displaced by a first means (27) for instituting axial displacement of the ring gear (18);
• a first coupling ring (10) for engaging a high-range mode and a second coupling ring (16) for engaging a low-range mode, the ring gear (18) being alternatively engageable with the coupling rings (10, 16);
• at least one synchronizing means (15) with at least one friction surface (14, 22), the synchronizing means (15) being configured to synchronize rotational speed difference between the ring gear (18) and one of the coupling rings (10, 16) by interaction with a corresponding friction surface (13, 23) arranged on the respective coupling ring (10, 16);
• the synchronizing means (15) and the second coupling ring (16) being arranged coaxially outside the ring gear (18);
• at least one second means (25) for engaging at least the second coupling ring (16) and a third means (25, 25b) for driving said synchronizing means (15) are arranged on a radially external side of the ring gear (18) and the second coupling ring (16) is arranged between the synchronizing means (15) and the first means (27).