Shim location
WARNING: This page is about a different car, the 2004 Volkswagen R32. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of VOLKSWAGEN UNITED STATES, INC.
S1 - Adjustment shim for friction torque/tapered roller bearing - head bevel gear
S2 - Adjustment shim for head bevel gear
S3 - Adjustment shim for shaft bevel gear