Yep,
Most likely bad pinion bearing. BTDT. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Evans Waldron
Sent: Monday, August 31, 2009 8:28 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Reverse Gear Problem - 4 speed manual

Hello All,
Got back last week from a 2250 mile trip in my 1983 water cooled Westy and when I was backing into my driveway and after about 6 feet- Bang! - was like I hit a wall or something.  Got out - no wall. Tried again and same thing.  Got a suggestion to check the rear breaks.  Was unable to get a drum off so went to my local foreign car (not VW) mechanic who found leaking rear cylinders and hung up parking break.   Fixed break parts and as he was backing out - bang! same problem.
Do transmissions fail like that?
Only happens with clutch engaged and in reverse.
Any else I should look at?
--
Evans