This could be the last straw for this 08 F150. It has always had this clunk in the drive train when accelerating from a stop, off and on.
Had to pull over on the interstate after the truck slowed put rpms didn't. Also a whining noise coming from somewhere. After pulling over, noticed the smoking diff. I'm guessing the diff is dry or very low on oil. How much potential damage will I be looking at when I pull that plate off? What if I just top it off with diff oil?

 

Hi there! Can you send us a PM with your VIN and Ford dealership information? I’d be happy to look into this on my end.

 

I would remove the rear cover and see what I could see. Look for metal particles. Probably needs a rebuild.