Busy swapping the diffs over in the wagon. Just opened up the back of the LSD and drained it and took this picture. there hasn't been any metal bits or anything come out in the oil - so it seems pretty good to me!

http://img507.imageshack.us/my.php?image=dscn14247my.jpg

Looks okay to me single spinner 2.72 or 3.08:1 ratio

I doubt you (or many people) can tell that a diff is in good conidtion just by lookng at it. Sure if it has metal shards in the oil or there is visible wear of the crownwheel teeth then you know there is something wrong. But if you ask me the only way to do it properly is to measure the clearances etc, and physically dismantle the diff to check the wear of the cones etc.