Just had a quick read through the service history and the ATF used was G052162A2 which is the Audi part number, however I'm pretty sure Febi make an OE replacement fluid under the same part number which is red. Still, it's not the proper Audi fluid. . . It was also £39.05 for 5 litres which is cheaper than genuine fluid.

Does anyone think that the mixing of the 2 fluids is what is causing the problem now?

I'll refer to my original advice which was to get it done professionally by someone who has the equipment to flush it properly. There are plenty of citings here about gearbox failures after an amateur fluid change, usually thought to be due to 'distrubing the sludge'. I'm not a gearbox expert, but I'd guess that mixed transmission fluid is not a good idea.

When I had a lengthy conversation with a tech guy from ZF, he said that it simply isn't possible to "flush" the transmission due to the design as there will always be fluid left in the TC.

If you have a good knowledge and experience of mechanics, a drain and fill procedure is really quite straight forward. If you have actually been through the process you'll see that (in my case anyway) it's not actually possible to disturb any "sludge" as all the contamination is being removed from the sump when it's taken off and cleaned. Anything else will be inside the transmission and out of reach of the localised work that's being carried out.

If you think about it, the internals of the transmission are draining every time you turn off the engine, the only difference with a drain and fill is that you're changing the fluid.

I would have had the same issue if anyone else had carried out the service and would have had to pay them for the same outcome. The long and short of it is, it didn't have the ZF/Audi fluid in the transmission and so inevitably the 2 fluids mixed which is why I think I'm now having problems. I unfortunately couldn't tell what fluid was in there before the procedure was carried out and anyone else doing the work wouldn't have been able to tell either.

I wonder if the filter screen on the TC clutch solenoid is partially blocked?

I'm looking for some useful input by other mechanically knowledgable people who may have had the same experience as me. I can't believe an Audi garage (York Audi) put a non genuine fluid in.

Hi Mugzee,

Sorry to hear about your woes. Just to confirm that the gearbox oil was not changed during my ownership (really due to consensus around just leaving it given the issues some have seen after a change) and that York Audi would have been the last place it was done before my ownership.

Hope you get it sorted.

Oli

Thank you Oli, that's good to know. It's annoying as even though that was the last time the transmission was touched, I have no real way of proving that. They also only carried out a drain and fill and didn't renew the filter, even though they were requested to do so.

I spoke with Tim from ZF and he said that it's probably bad news. Mineral based fluids are usually red and when introduced into the gearbox can and will damage clutch plates and seals, even the possibility of de-laminating clutches. Mineral and synthetic oils don't mix well and he said that is probably what's causing the issue. Without getting the old fluid analysed, it's obviously difficult to tell exactly what it was.

On another test drive to try and determine when the fault arises, it went into limp mode with 17114 - gear ratio monitoring fault code.

I may try another fluid change to see if that helps.

This is a real shame to start your '8 ownership with problems. If you want to talk to another ZF expert, this is the guy Brian and I have used:

J Connachan
Service Manager
Mackie Transmissions
Tel: 0141 778 4545
email: jconnachan@mackie-transmission.com
Web: www.mackie-transmission.com

Thank you. I called them today. I was told I was going to get a call back but I didn't so they must have been busy.

Tim from ZF called me back with some more info today. He told me to carry out a stall test to determine whether the clutch packs are at fault. He also said that a bulletin had been issued regarding faulty coolant temperature sensors which can indirectly cause transmission issues and problems with shifting even if no fault codes are present.

I have also found out that Audi and ZF lifeguard 5 fluids are Mobil ATF LT 71141 rebottled.

That makes total sense as Audi and ZF are not major oil companies and wont be producing their own oil. What is intriguing is that the designation "LT 71141" is identified with an Esso product in the linked Mustangbuffs article earlier in this thread along with a statement that Mobil didnt produce a compatible ATF! What is true is that Opie and others stock Mobil ATF LT 71141 at £10.49/ltr from their site or £8.38 thru' their ebay site. (delivery extra)