opinions on my differential dilemma

[bosephus]

Hi all! I have a 61 chevy with what I believe is called the HT55 rear end(drop out third member 3.90/1) that is leaking oil at the pinion.This rear end has a limited slip carrier and the ring and pinion looks fine to me(which means I don't see any huge pits or missing teeth). I also have at my disposal a 12 bolt 3.73/1 truck rear from a 65(I think) that doesn't have the limited slip and needs to be rebuilt.I dont know which way to go on this one.Are there parts still available for the HT55 and where would I find them?Is the HT55 worth rebuilding or should I bite the bullet and buy the parts and limited slip for the 12 bolt?Should I just keep adding oil and call the resulting mess rust preventionAlso,I dont mind the steep gears because i'm running a TKO overdrive transmission.Any input is appreciated(I think) Thanks