I bought the above truck in August. It's a quad cab if it makes a difference. Anyway, the truck doesn't get driven alot. Weekends only. Mostly hunting. Since I bought it there has been some vibration (almost jumping) under light acceleration only. Only when the truck had been driven a while not while just putting around town. It seems worse when the wheels are turned sharp. It seemed to be coming from the rear end. About a month ago I got tired of it and took it to the local shop and had it and a couple other "minor" things fixed. He said it was "tight" ujoints on the rear drive line. So I had him change them out. I didn't drive the truck much until Easter weekend but I didn't notice it anymore. We took the truck to Washington state, about a thousand miles. In the middle of the trip I noticed the vibration again. After probably 600 miles of high speed interstate speeds with little stopping. After we got there and everything got cooled down it seemed to be better but on the way back, same thing. Yesterday we went bear hunting and there wasn't alot of high speed stuff but the truck was driven basically from 3 am until 6pm non stop. It started vibrating again and this time when I got on the highway it was vibrating at higher speeds, also. Not bad but almost like a ujoint would(they're brand new). When I got home I could smell what seemed to be hot gear oil near the back of the truck. The question is this. Is it more than likely the rearend? Should it just be replaced? Or could I try replacing certain components including all of the gear oil? If it is worth changing a component, what should I change? Sorry for the novel, I hate posts with no details.