Had a 77 Westy that did the same thing.  Turned out to be the 4th
gear synchronizer ring.  Replacement requires disassembly and a rebuild.

But it could be something else, such as shifter, shifter rod or side shift
rod attachment at the transmission.
--
Jim Thompson
84 Westfalia 2.1 "Ole Putt" (with Auto Trans)
73 K Ghia Coupe "Denise"
72 411 Station Wagon "Pug"
oldvolkshome@gmail.com
http://www.oldvolkshome.com
**********************************
On 12/2/06, Susmay <susmay@yahoo.com> wrote:
>
> Driving along at 60 or so and about once every 1,000
> miles it suddenly is in neutral, engine racing, pulse
> too. It goes right back into gear and then drives just
> fine. It has not done it at lower speeds, or in any
> other gear besides 4th.
>
> The WurstFalia is an 88 which had a Tiico engine and
> new clutch about 3,000 miles ago.
> Any suggestions gratefully welcomed.
>
> Thomas Hawkins