Three Flywheels later

I have NO idea what is going on. I bought a 93 Rodeo 2x2 automatic trans the motor seized and I replaced it with a 95 since then I have broken three flywheels my mechanic has no idea what to do I am thinking of taking to a dealer to see if they can tell me what is wrong but I am hoping to get some help here first, thanks

easy there is a part that did not get put into the crank similar to a pilot bearing but its not a bearing it is designed to center the torque convertor if its not that then there are dowls missing between the trans and bellhousing