you guys were right I apologize, the number on the spines is identical but the backlash/spline size is different ever soo slightly, the rv trans has 4 pinion's on both sets while my 76 trans has 4 and 3, interesting. thanks. rv trans low/reverse band is completely chewed out however everything else looks barely broken in, have to check out a few trans shops and find an output shaft that will work for the 73...