i just had an 85 1.6 turboDiesel engine installed in my 82 Westy along with an 85 4 speed (bought as an 83 5 speed) transmission.
i learned that the later Diesel gearbox mounts about an inch toward the passenger side, takes a late style shift linkage, and is engineered for different engine support bars and mounting brackets. the Turbo requires different drivers side support bar and bracket from the NA engines. The passenger's side bar can be used, but the turbo oil fill tube won't clear.
it was quite a project without any of the proper parts, but we fabricated a working set up from the early bars and brackets. and if you heard that a 5 speed for the Diesel vanagon has a different shift linkage than the 4 speed, not true. the difference is between early and late style shift linkage. all 82 Diesel tranys were early style; 83 5 speeds could be either.
any questions on the project, don't hesitate to ask.