S8 transmission service

[SharkGill]

Following on from my transmission limp mode episode the other day (P0730-35-00 Incorrect gear ratio) I decided to drop the fluid today. This job was supposed to be a quick in and out but I knew things were going south after I stripped the first torx head on the sump bolt.Someone previously had replaced a couple of them with 10mm headed bolts so the sump has definitely been off. I ended up stripping around four in total. Good news is that a 12 point 11mm socket hammers on perfectly for extraction. Sump removed revealed a filter as old as the car and with the housing cracked. Someone has definitely has tried to service this but maybe didn't know how. Turns out I somehow managed to order the incorrect filter. Turns out MJ was spot on about the fluid level being too low. I managed to drain around 6 litres. I had no choice but to put fresh fluid in as I needed the it mobile and off the ramp. I managed to fill over 7 litres.
Good news is there was no metallic 'glitter' in the fluid so I'm hoping the transmission has a bit of life in it yet. I ordered brand new sump bolts from TPS costing around £70 on trade so I'll be replacing them along with the new (correct) filter when it arrives. I did take it up the road just to turn it around and I noticed the 'supercharger' whine is gone.

I couldn't find any decent guides on refilling, even my copy of ELSA was blank in this section. I followed the process below, Please comment on how it could be improved/corrected


1. Used a pressure filler connected to the drain plug and filled 6 litres (less mess)
2. Started the engine and filled another 2 litres
3. Disconnected pressure filler and refitted drain plug
4. Cycled through the gears whilst waiting for the transmission temperature to reach 30 degrees celcius
5. Drained off excess fluid from fill hole until fluid dripped out (as opposed to a steady stream)
6. Refitted fill plug

S8_filter.jpg

[HPsauce]

I found this online from the USA: https://audi-d2.com/docs/technical_main ... placement/

[MikkiJayne]

Well that filter would explain the whine and clutches slipping, since the pump could be cavitating if the fluid is low.

If I'm reading it right, you've had to put the broken filter back in? Not optimal, but if the ATF is covering the crack, not terrible to get it moving.

Make sure to measure the pickup spout on the new filter relative to the sump. Occasionally the RS6 filter gets cross-referenced and that has a deeper sump with longer spout which doesn't work in the D2.

Otherwise, a relatively easy fix