BMW (English, Русский)

3-series E30 325iX 1988-1992(Edit)

Full-time all wheel drive. Viscous coupling locking center differential with torque split 37% front / 63% rear. The viscous coupling is integrated into the planetary gear center differential. viscous coupling locks the differential when wheel slipping occurs and transfers up to 90% of torque to the axle that has traction. Viscous coupling locking rear differential distributes torque between the rear wheels.

Figure: BMW E30 325iX transfer case

Figure: BMW 325iX

See also: Viscous coupling

See also: Viscous coupling locking center differential test

3-series E46 X models 1998-2006(Edit)

Full-time all wheel drive with all free differentials. 38% front / 62% rear torque distribution thru planetary gear. ADB-X (Automatic Differential Brake) electronic traction control performs functions of locking differentials.

3-series E90 X models 2006-...(Edit)

xDrive.

5-series E34 525iX 1991-1996(Edit)

Full-time all wheel drive. Torque split 36% front / 64% rear. Computer controlled system using the ABS sensors to detect wheel slip.

The E34 system exists in 2 generations with a major difference:

Generation 1 has separate control unit which control electromagnetic semi-wet multiplate disk clutch in centre and electrohydraulic wet rear differential. It recieves ABS wheel sensors data signals from special, modified ABS unit. Front differential open. In production from april 1991 up to september 1993.

Generation 2 has ABS/ASC+T unit which controls semi-wet electromagnetic multiplate disk clutch in centre and an open differential rear through rear wheels brakes (ABD). It also controls throttle. Front differential open. In production from October 1993 up to end of production.

Most components looks very similar to 325ix E30 models but are unique parts.

Figure: BMW 525iX E34 - 1st generation

5-series E60/E61 2004-...(Edit)

xDrive.

X3 2003-...(Edit)

xDrive.

X5 1999-2004(Edit)

Full-time all wheel drive with all free differentials. 38% front / 62% rear torque distribution and ADB-X (Automatic Differential Brake) electronic traction control performs functions of locking differentials. Hill Descent Control (HDC).

X5 2004-2007(Edit)

xDrive.

X6(Edit)

xDrive.