My guess would be that a bearing in the alternator is dying.

     > -----Original Message-----
     > From: Vanagon Mailing List
     > [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
     > Of John Meeks
     > Sent: Sunday, October 19, 2003 5:52 PM
     > To: vanagon@GERRY.VANAGON.COM
     > Subject: Strange new noise - EEEeeerrrrrrr
     >
     >
     > Esteemed Litstees,
     >         I first heard this sound 2 weeks ago.
     >
     >         SCREEERRRrrrrrrr. Like a heavy desk with legs being
     > dragged a few inches
     > across a hard bare floor It only lasts for 1 - 2 seconds,
     > maybe once every 3
     > days, only once happened twice in one day.
     > Doesn't matter if it's cold or hot (engine OR weather),
     > uphill or flat,
     > cornering or straight.
     >
     >         I can feel a vibration in the shift handle but it
     > vibrates the whole van.
     > The sound is like a belt slipping but lower pitched and
     > more mechanical. It
     > is definitely coming from the rear.
     >
     >       Anyone ever heard this before? All comments welcome.
     > BTW after I first
     > heard this sound I drained my tranny (with a rear tilt to
     > get that last 1.5
     > pints our) and replaced with Redline MT-90.
     > Shifts smooth as silk but still get the noise from hell!
     >
     > Regards,
     > John Meeks
     > Top of Lower Michigan
     > 91 Westfalia MultiVan
     >