> Amazingly, after adding 1/2 of regular 75w90, the noise is almost
> completely gone! This noise had been present for several years,
> and possibly started soon after I added Redline MTL...

And herein lies the rub, IMHO:  You added fluid, period.  My guess is that your
Vanagon tranny has a slow leak and the fluid level is low.  Unless I missed it
in your message, you didn't say you've checked the fluid level.

I'm running Redline MT-90 on a fairly new tranny and it's nice and quiet.

-Karl

Karl and Kristina Bloss, Trexlertown, PA
'87 Westfalia Weekender  "Beverley" - 196K miles
http://www.enter.net/~bloss/vw/
PA/NJ Vanagon owner's mailing list: http://www.enter.net/~bloss/vw/pavanagon/