I have been chasing a vibration in my F250. When I am driving my truck and hit a small or big bump in the road, I get avibration just like I am driving over rumbel or wake up strip along the road. If I turn on my 4 wheel drive switch the vibration goes away immeditly and I can switch right back to 2 wheel and have no vibration until the next bump. I have changed both front hub assembly then I removed the lock outs to try and isolate the problem, still no change. I almost feel like a drive axle goes into a vibration, but I would think they are not even turning until I turn on the 4x4 switch to get read of the vibration. CAN ANYBODY HELP.