Soooo, it is fixed, no more clunk!!! So, it ended up being a undersized bolt that was put on before I bought the truck. I don't know what they are called but the long bars that run from the front suspension to the middle of the truck. The bar was lose and clunking. Put a 2.00 9/16 bolt in, and no more clunk!! Not mad at all that we replaced the pit man and idler, they were sloppy anyway. Can't belive it came down to a 1/2" bolt! Go GMC!!!! Thanks for the input guys.