I have a 2004 Ford 5 man cab F-150 with 118,000 miles, a 5.4 and auto trans with O/D and 4 X 4. The slack, or play between coasting and accelerating has gotten so bad that I can't go on a slight down hill grade with the cruse on cause it starts to hammer between coasting and accelerating, like there is too much slack in the drive train. The U-Joints look very solid.
Has anyone else having this problem? And if so, was it the trans, transfercase, or the rear end?
Thanks,
Matt

 

I've heard that the drive line splines can get really dry and need to be greased. Use Fords Motorcraft "PTFE Lubricant" if you decide to grease them up.

 

Most likely just the wear and tear from the mileage.