Faulty AWD coupling unit/transfer case


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Dec 7, 2012
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Melbourne, Australia
Hi all, ive only done 40,000 kms in my 2016 RS3. And developed a vibration from the rear upon acceleration. I noticed this after my right quarter panel and rear wheel was repaired after an accident.

Audi spent 2 days trying to find the problem, and found it to be the AWD coupling unit has failed. I believe it’s also called a transfer case. They couldn’t provide a reason why this part has failed, and say it wouldn’t be related to the accident. it’s $11k aud to fix, cars only worth around $60k.

anyone know what causes this unit to fail? Had a chat to another mechanic, and he says he is starting to see a few more RS3s with this problem
If it is the Haldex unit then it is a well known problem when the Haldex is not serviced properly. Audi do not service it properly. The Haldex V does not have a separate filter like the Haldex IV but you still need to take the pump out and clear the screen filter attached to the pump. May just be the pump failed but if the pump has failed a long time then it may have taken out the whole unit.

If it is the rear differential then a common problem is confusion between the oil drains of the Haldex and the rear drive as they are very close. Would not be the first car to have drained the rear differential by mistake leaving it with no oil The overfilling the Haldex.
I had the s similar issue but more a drone than vibration (i think that means yours has fully failed) - light rear shunt, although i think the transfer box was already failing but that made me keep an ear out for it. I found a specialist here in the UK who have refurbished it for me - new bearings e.t.c. £700 in total.

$11K sounds crazy! new transfer box for me would have been £3500.

Its very common - garage i went to has an RS3 booked every day for the next month, same issue, droning under low acceleration at around 60 mph and a stuttered noise when you left off. Apparently Audi are fully aware, still fitting the same part on new cars and even worst that its avoidable by just having the fluids changed more regularly.

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