I was driving my 08 F250 4x4, 6.4 @ 30 MPH in stop and go traffic. I slowed to allow a car to turn in front of me. When i accelerated, I felt a tremendous "bang" or bump from my rear end. It was so noticeable that I thought someone ran into the back of my truck. The truck drove and shifted fine after that and had not repeated it "yet". I have owned ford diesels for years and have owned every make and model. I have NEVER experienced this before. Has anyone else experienced this ?? Thanks !!! Wade