Was running the truck during our recent heat wave when it started a howl/squeal. Hit the AC button and noise stopped. When i had the time i checked the belt (was on it when i bought it to years ago) and the tensioner is near its limit. When switched on the clutch does not seem to be spinning at the speed it should and it howls/squeals. I have a belt ordered. I believe it takes an FS20 compressor and am wondering if that compressor is the same for all wheelbases. I found a very good deal on an FS20 and am considering buying it. I would then have a completely new clutch set up to put on the old compressor if it turns out to be more than a belt, and the compressor itself if need be.