Car makes loud scraping and grinding noise

I have a 2004 f150 heritage 4x4 when I put it in reverse it binds up then bucks and makes a banging noise then in drive it makes a loud scraping and grinding noise it just did it suddenly while backing up any idea what it could be? It happened suddenly I put it in reverse and as I started moving it started locking up and bucking so I tried drive and when I move it makes a grinding and scraping noise. I looked under it with the tires up off the ground but could find nothing wrong.