Any chance the ayc and diff oil can mix?

[chugg]

Hi people, wonder if anyone can help me?
The car has had a bit of a drone from the rear for a few weeks, at higher speeds and when slowing down, so I was just changing the oils in the rear diff as they've not been done for a while, and when I dropped the gear oil it looks pretty red in colour. No sign of any leaks on the diff. I've always filled up with amsoil all round and diff was amsoil severe gear.
Is there any chance the atf from the ayc clutch side can get in to the diff side through a duff seal or anything?
The ayc has been out of action for about a year or so anyway, all lights correct on start up but then you can hear the pump whirring for 30 seconds or so then just stops and the red ayc light comes on. I just put that down to pump failure but now wonder of that is somehow related? I do have a new adjustable switch from malc but never got round to fitting it. The atf for the hydraulic res part in the boot is at the right level.
I'm just going to go ahead and put fresh oils in anyway and check them again after a few miles.

[Davezj]

if the ayc system is faulty you should pull the the ayc fuse out to stop ayc system from trying to work. otherwise you are just trying to constantly run a system that tries to work and then fails which will harm the system that has failed.

the fluids in the rear diff should not mix under any circumstance, if it has then yes that signifies a seal has failed and the diff is knackered and will need fixing or replacing.

[chugg]

Cheers for that Dave. I'll do as you suggest and pull the fuse.
Guess I'll just check the new oil after a few miles and see its condition and see if its had it. The old atf was as cherry red as the day it went in.
I suppose it's at that point where I need to decide whether to keep it and chuck some £££s at it (have had 6 years good service from the ol' girl) or move on.

[chugg]

Changed the oils and been for a run but the droning noise still seems to be there.

[Nick Mann]

I have seen a diff where the seal had obviously gone between the diff and clutch packs. The amsoil came out the same reddish colour everywhere. That owner decided to replace the rear diff, IIRC.

[Davezj]

you can pick up vr4 rear diffs for about £100 and swapping is not a massive issue.
so no big deal really

[chugg]

Thanks Dave and Nick. If it turns out to be dud I'll probably see if I can pick up another diff.