Vaseline.  Dip finger into a tub of it; apply the thinnest film you can onto sliding surfaces of Vanagon window ledges.  Thinner the better.  Work it around a little bit, imagining all the contact points.  Work window back and forth.  Use rag to remove excess.  Works wonders.  No more screetch.
After a few months, if screetch resurfaces, do same treatment again.  Yes, it wlll collect a little more dust.  So what.  Wipe it off.  

Rich
San Diego

      From: Ralph Meyermann <ralphmeyermann@GMAIL.COM>
 To: vanagon@GERRY.VANAGON.COM 
 Sent: Tuesday, June 19, 2018 5:57 PM
 Subject: Westy sliding windows.
   
I have heard rumors of rebuild/seal kits for the sliding windows on westys?
Any truth to that? Thanks, I'm tired of the screetch.