My fathers 2003 6.0 has never had a significant problem even...knock on wood!!!, all of a sudden this morning the truck wont move an inch, it starts and runs fine. put it in any gear and it acts like neutral. When the gear shift is put back into park it grinds a little bit. i looked underneath and the cable going into the tranny is ok, it moved perfectly.. i searched for DTC's and didnt come up with anything.. any ideas?!