These sounds could be a pain in the butt !
Had a similar experience with a Thule roof rack that I used both on the
Vanagon and my daily driver with two different sets of feet (different
height)
I was in a hurry when I put the rack on and after a while I started to hear
a deep kind of howling sound .
It grew worse when i picked up speed , people turned and looked and my dog
seemed to be annoyed too so I stopped to find out what the problem might be
!
Found nothing so I took off again with the same sound comming back.....
Turned out to be the end caps on my rack that was left behind in the hurry
with the same sound as when you blow across a bottle as a result :-P

Calle

----- Original Message -----
From: "Kim Brennan" <kimbrennan@MAC.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, June 02, 2004 11:58 PM
Subject: Odd sounds

> So, I was coming back from the Memorial Day weekend, and I kept on
> hearing odd sounds. Sort of a rumbling grumbling, vibration sound quite
> unlike anything I had heard before. It only occured once I got above 40
> mph, but wasn't constant. At first I was thinking maybe my front inner
> CV was going bad (torn boot that will get replaced RSN). But the sounds
> didn't sound right for that.
>
> It took me a while to finally identify the culprit. The straps holding
> various stuff up in the luggage rack of my Westy. Seems I had tightened
> them up just enough so that they "sang" in the wind. Gah,
>