I'm wondering if there are certain models that have the lsd 4.44 which could be a direct swap? I found a 4.44 lsd from a 00' impreza rs that looks like it could work but will it? If I can get by without having to remove gearing and worry about backlash and preload I may go that route.
History: A year ago I swapped in a 4.44 tranny, I did that and the differential work myself. I now have a whine coming from the rear. It wasn't very audible at first but now it's really making noise. Loudest is at around 55mph. It sounded like a rear wheel bearing and I was told that my rear right was bad so I replaced it and the left.
Now I'm thinking I have a bearing going out in the carrier. Last fall I was able to put the fwd fuse in which made the whine significantly less noticeable.
Found the answer...
http://wac.addr.com/auto/obs/lsd/lsd.html