Power Flow - Front Wheels Slip
WARNING: This page is about a different car, the 2006 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
When traction is lost at the front wheels, the viscous coupling works in conjunction with the differential to bias the torque more to the rear wheels. The rear torque goes higher than the 62 percent, and up to 100 percent torque to the rear output shaft (2). The torque at the front output shaft (3) is lowered from the 38 percent, to as low as 0 percent torque.