Unless I'm mistaken, and I may well be, the original M915 had the old body style, a 400 Cummins, 16 speed CAT semi-automatic transmission and fixed 5th wheel, the A2 had the old body style, 400 Cummins, 5 speed Allison automatic and a sliding 5th wheel, the A3 has the Freightliner cab, a 60...