Hello,

Sounds like it could be one of a couple of things but I would
suspect the pinion bearing is probably worn.  The noise (soft
whine type noise) be there in first as well but you may not
notice it will all of the other noises the Van is making while you
accelerate.  You can hear it in 2nd due to the light load thats on
it at the time.  Take it to a trusted local VW mechanic and pay
his diagnostic fee and see what he has to say.  If something is
going 'south' on you I would fix it before I left on any trip.  Being
stuck in town is one thing but being stranded in someplace
strange is another!

Also, the difficulties engaging 2nd is usually caused by the pin
that supports the 1st/2nd fork beginning to stretch.  Eventually
it will snap and you will not be able to get either 1st or 2nd.  VW
updated this part on later models and I either modify the existing
fork if not too bad or replace with the new style fork during my
rebuilds.

Good luck and keep us posted!
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Todd Hill
VolksWerks Transaxles
Olympia, WA