Steve Hannes: These discs are "slipping" in normal operation. When there is a significant difference in rotational speed between the drive and driven discs (as in rear wheel slippage), the special viscous fluid heats up, expands (actually gels) and the friction between the drive and driven discs locks them causing a torque transfer to the front wheel output shaft. As soon as the drive and driven shafts slow to a closer matching speed, the fluid cools, thins, and unlocks the drive/driven discs freewheeling the front wheels again. This is all there is to the X-Type AWD Transfer system. There are no electronics controlling the torque distribution in this system. **** more info: http://jagmotorproject.blogspot.com/2007/02/motor-project-17-transfer-time.html ****