I have an '86 Vanagon Westfalia and sometimes when I round corners quickly
I get a funny grinding noise in the back.  It is very distinct, and it is
either there or not there; when you hear it is the same volume.  Sounds
like a tire rubbing but it seems to be related to engine speed.  The tires
are the stock size and there are no visible signs of rubbing.  So I
replaced the four rear engine mounts which didn't look so good; so I
thought that was it.  Nope.  I checked the rear wheel bearings and they
were loose.  Changed those out.  Nope.

So I am thinking maybe it is the transaxle mount?  I can't see anything
under there that looks like it is rubbing!

Thanks,
Ryan