I recently bought a rear (rotor to rotor) from a guy on craigslist,he told me that it was from his wife's car that had been hit bad in the front,and that he bought a shell and transferred everything over except the rear,which he pulled and held on to.well when I went to get it it seemed to rotate smoothly,so I bought it and proceeded to install it,after it was installed I weas turning the pinion flange and it locked up at the same spot,so now my spyder senses are tingling,and I pull the cover,and low and behold the ring gear has like 7or 8 teeth that are rusty.I pulled the carrier hoping it was just surface rust,but it seems like some of the teeth are pitted.so I call him and he says that all I need is a new ring and pinion,and that the housing and carrier are fine,which may well be the case,but im gonna have to spend like $300 bux for r&p and bearing kit.he totally screwed me.but I still know where he lives.