So as we ponder what to do with our various tractor pieces, my father and I were wondering if it would be possible to swap the complete rear end, ie from behind the trans, from the 671 to his naa which has a loose axle spline and some 3pt issues. will they bolt up? pattern looks the same but wondered about the insides, I know I would have to swap the pto parts from the naa to the new rear end. Also I know the hydraulic lines are a little different, the 671 being internal, but from looking at the casting I see the same cover on the bottom where the naa lines enter so thinkin I can make that work.