Just perhaps ...did you check the tranny cable from your shifter. The bracket that holds the cable to the tranny could be loose. When I built my first Drag truck I had the same problem ..I could not get into gear, the shifter moved but the truck did'nt. I tore the whole thing apart oneday when my Ol' man came up and he said " Did ya tighten your linkage bracket" .....Uhhhh Duhhhh. Worked fine till I sold it.