Drive assembly for a four wheel drive vehicle, having a disconnectable viscous coupling

摘要

A drive assembly for a four wheel drive vehicle, which drive assembly, during forward driving, automatically assumes a freewheeling position if the speed of the dependent wheel axle is higher than that of the permanently driven axle, with the four wheel drive function otherwise being maintained with a reduced driving torque, even during reversing, the drive assembly providing the freewheeling unit with a second viscous coupling which is connected in parallel and whose torque transmitting capacity is smaller than, or equal to, that of the first viscous coupling.