Starter Problems

Recently my Bronco II started making a high pitched grinding noise when I started it. So I replaced the starter. The remanufactured starter worked for a couple weeks then started making the exact same noise. So I warrantied that one out. I installed the second one I got and it didn't even turn the motor over, just made the same high pitch grinding noise. I did notice the first remanufactured one I pulled the teeth on the starter gear were worn. Is there any way to tell if its the fly wheel? Or maybe the engine seized? It was running fine when I parked it and has plenty of oil.