truck cap wind fairing

#1
So the cap on my truck (an aluminum craigslist special) sits about 2 inches taller than my cab, so it makes terrible wind noise from the tornado it sends between the bed and cab. I built an aluminum fairing to bridge the gap- it comes down to touch the cab roof, and it cut down on wind noise a TON; but on every bump the fairing squeaks on the roof of the cap.
Anyone have any ideas to stop the squeaks?

The fairing it self is pieces of 1/8 aluminum composite board with 1/8 inch ribs screwed into the cap, with auto door trim (the rubber C channel) on the edges to prevent scratching
 
#2
You could use a length of foam/rubber weatherstrip under the leading edge of it. I'm thinking the kind sold at the Home Depot. Also, maybe just try some wax or polish on the auto trim and cab.
 
#3
The problem results from the fact that the cab is mounted on rubber bushings and the bed is hard mounted to the frame. You need to allow room for the cab to move around by increasing the distance between either the cab roof or the truck cap roof depending upon which one it is mounted to. If you don't do this you will wear through the paint on the cab roof despite any efforts to the contrary. Best bet is to mount the faring to the cab roof with some rain gutter mounts if possible and leave room for the cap to move under it.
 
#4
The problem results from the fact that the cab is mounted on rubber bushings and the bed is hard mounted to the frame. You need to allow room for the cab to move around by increasing the distance between either the cab roof or the truck cap roof depending upon which one it is mounted to. If you don't do this you will wear through the paint on the cab roof despite any efforts to the contrary. Best bet is to mount the faring to the cab roof with some rain gutter mounts if possible and leave room for the cap to move under it.
that's what I was assuming the issue was, not having any sort of gutter setup and not having see one that wouldn't hold the fairing over the roof substantially, I was thinking that I might try making the fairing shorter (only as wide as the gap between them)