Ok, my buddy mark blew his rear end so we just dropped one in on friday night in his 2001 f-150 (4.6 L if it makes a difference) and last night he took it for a test run and it "locked" up into drive (last gear before OD), no shifting at all, cant get it moving unless its on flat land because its in really high gear. The overdrive light was flashing, and the Check engine light, could this possibly be a torque converter? or tranny issues? It did have a nasty clunk into second previously from all the **** hauling he had done to it.

 

First thing to do is get the codes read out.