Audi R8 2008 Service Training Manual page 41

Viscous Coupling
Power to the front wheels is through a two-piece, center
bearing supported driveshaft. The driveshaft runs from
the transmission through the engine oil pan to the front
differential. From there, a viscous coupling distributes
power between the rear and front wheels.
The system was adapted to the mid-engine layout, with
its ideal axle load distribution of 44:56 percent. The
viscous coupling directs between 0 and 35 percent of
the engine power to the front wheels.
Drive Shaft
Center Bearing
Two Piece
Drive Shaft
Transmissions/Driveline
Front Differential
Viscous
Coupling
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