5HP24 filled with red ATF - how bad?

[MikkiJayne]

Hi guys,

I realised today that at some point in the past my S8's gearbox has been filled with red ATF, rather than the proper G 052 162. I'm hoping it was the PO who claimed to have had the oil changed just before I bought it, in which case its only done 300 miles like this, but it may well have been in for longer.

Is the wrong fluid likely to have done any damage? It was behaving fine on the way home so I'm hoping a re-fill with the proper stuff and a new filter will be all it needs.

I've got 0.7L out of the torque converter, and whatever comes out of the sump (~4L from what I've read), but I think that leaves a few litres still in there somewhere. Will it drain over time with the sump off, or does it need taking apart to get it all out? Given that it was working I'm reluctant to take it to bits!

Thanks all