I have placed a copy of Wolfgang Peschke's paper "A Viscous
Coupling in the Drive Train of an All-Wheel Drive Vehicle"
onto the Syncro files at Yahoo!  Mr. Peschke was one of the
development engineers at Volkswagen when the VC was
developed.

http://groups.yahoo.com/group/Syncro/files/Viscous%20Coupling%20Paper/

Good technical reading.

Keith Adams
Calgary, AB, CA
86 Westy "Roxy" / 87 Syncro "Hugh"