Just thought I would pass this along- My '07 6.0 was experincing a vibration at idle in gear that was rattling the entire truck. As soon as you gave it a little throttle, it went away. I have read many posts on vibrations, and they all point to the "obvious"- exhaust, belts, etc. I took the truck in under warranty, they "checked" everything and couldn't find it, and just before they were going to pull the tranny, someone at the dealer found the left mid body mount grounding to the frame. They replaced the body mount and bolt, and presto! no more vib.