If you are rebuilding the transmission then this is the set of gaskets you need.
Drive Shaft Flange Seal on Syncro Transmission
Shift Linkage Boot 86-91
Viscous Coupling Syncro
Shift Bushing for 84-91 Vanagon center or rear
Vacuum Acutator for Syncro Vanagon Locking Differential
Syncro Transmission Output Shaft Bearing