Hi Folks, hoping I can get some advice from someone. I have a 04, 4 door, 4 wheel drive, automatic tranny, short box. I noticed a slight vibratiion a few months back that started at 55 mph and carried through 65 mph in a pull, didn't do it just driving along. Kind of ignored it for a while, seemed to be worse when the truck was cold, then got a bit worse as time went on. Took it to the Ford boys and had the diesel guy look at it, didn't have any suggestion. It has steadily gotten worse, last through about 70 now and vibrates hard in a pull in the hi gear, will quit when you drop a gear or back out of the pull. I put a new carrier bearing in, no slack in u joints. I do not know what to do, I believe something is going to blow up, just don't know when, I would like to figure it out before diaster strikes. Looking for any help I can get, open to all suggestions for things to look at. thanks in advance.