i just had a 00 500 quad master gave to me...it runs but the front diff case is cracked...im gonna try and have it welded but its cast and have doubts that it will hold up...so what all differentials will interchange with this....or do i have to buy the exact differential case for the quad?

Try a little JB Weld on it. My son used some on an exhaust manifold crack it held for years...Bob