I posted a problem with my four wheel drive were as when i drove in 2hi it was fine but when i switched to 4hi the truck would sound like i was driving over gravel or road salt and as i would start to turn the truck would start to slow to a stop but once i put it in 2hi it would drive fine. Well for the time being i have been driving in 2hi and i just got a chance to check under the truck and found that the tansfercase had been leaking so i think that is the problem.