MOTOR VEHICLE TRANSMISSION

摘要

In a motor vehicle transmission a first rotary member (43) is connected to a second rotary member (47) by a variable resistance coupling (40). The variable resistance coupling (40) comprises a first viscous coupling (45) connected in series with a second viscous coupling (48) by a common outer housing (49). A selector clutch (50) can connect the outer housing (49) to the second rotary member (47) to render the second viscous coupling (48) ineffective and give a high resistance mode for the variable resistance coupling compared to the low resistance mode when both viscous couplings are operational. The variable resistance coupling (40) is used to control the centre differential (17) in a four wheel drive vehicle. In an alternative arrangement (fig.3, not shown) the variable resistance coupling is in the drive from an intermediate reduction drive driven by a conventional front wheel drive engine and transaxle and connects the transaxle to the rear wheels.