The chances for rust are outstanding for any rear end sitting stationary for 20 yrs, no matter what part of the country it sits in I took a 741 third member out of a 1965 A100 van in 1975 or so and it had sat in that junkyard in Hesperia, CA in the Mojave Desert for less than 20 yrs, it had rust on all the ring gear teeth above the lube line It did wipe right off and it wasn't pitted, I didn't buy it but someone else did and swore it was good later BTW, that one was 741 case with a 3.91 posi I should have bought it