I'm sure anyone who has the Screw has noticed how bad the buffeting and windnoise is if you roll down the back windows only.

This morning while washing my truck, I noticed that if you look under the rear wheel wells, there are 2 holes in the frame. One is round, and one is square. You can see all the way through to the other side.

Is it possible that wind going through these holes is causing the vibrations at certain speeds?

 

I dont think so. The pressure gradient below the bed is much different than the rushing air past the windows, and the cab pressure. The buffeting is due to the fact that the pressures cannot equalize. With those rear holes, the air equalizes very quickly because there isnt a 'pocket' maintaining the pressure (like the front of the cab).

 

If you don't like the holes, on e-bay they sell plugs. Just for cosmetics, though.
Chris

 

The buffeting is a "nature of the beast" thing. Alot of vehicals experience this sort of thing with the windows down.

btw, I bought some of the "plugs" off of Ebay. They are a nice touch.