Just fixed a similar problem in an 85 westy. If the vehicle has the problem
when the vehicle is nto running it is unlikely the syncro mesh. To aleviate
this problem if it happens while no running.Do the following...

 In the middle of the vehicle underneath ther is a Universal Joint at that
point there is a connection between the front linkage and teh rear linkage
loosen up this bolt that clamps the 2 linkages and adjust as need. The
easist way that I have found is to loosen up then turn a little, then shift
around till it is shiftin fine then tighten. Also while under clean up and
regrease all of the fittings that the linkage travels through including the
rear where it goes into the transmission. This should correct your problem..
If you have any questions email me back.

namaste
Stephen

85 Westy