Appreciate all the 2 cents I can get. I have had the cross member and the trans out over the years. The noise was there way back before that. However in my recent checking I have not looked at that cross member and will right now. I will also check the battery box. The battery is tied down tight.
One thing that comes to mind happened years ago. I had taken all the bed wood out for refinishing and at the same time I did not put the 6 bed bolts back in. I drove the truck like that for a week and realized there is nothing holding the bed in place except the fenders and the running boards. I replaced the bed bolts with a piece of wood the same thickness of the boards until I could put the bed boards back in. Wonder if this thump is a result of that period of time when I drove with out the bolts in place. That is probably when I lost the rubber pads too.
