I just removed the rear end from a 900 and am going to put it into a very nice 850 with a bad rear. First off, I hope I am right in that they are interchangeable. The gears and internals look great. My question would be does anybody have or sell a kit or set of seals and gaskets to refurb it while it is out, or do I just need to pick up the individual seals. Also, any input on what all to inspect or replace while it is out would be appreciated.