I've been having diff problems for a while now - noisy etc.
I was in the lucky position of having a spare, so had that fitted. This has turned out to be worse than the original, and sounds as if it's about to explode now.
Anyway - I stripped down the original one, removed the Haldex, there's a bit of rumble in the bearing there, but not too bad.
I stripped the side cover off the diff, out came the crown wheel and carrier, all looking good there.
The pinion shaft on the other hand, I managed to tap straight out with a mallet - the nut was not even on the threaded portion of the shaft - this was therefore floating back and forth in the housing and has polished a nice ring around the diff carrier.
What is the correct procedure for this nut - surely there should be some locking fluid on it at least? And what torque does it need to be tightened up to?
I shall get a new collapsible spacer and fit new bearings while I'm there.
I suspect 'someone' has been there before and repaired it previously.

If you can post some photos that would be useful for future reference.