Help! Issues with Audi dealership! Advice needed!

[Azmontana]

Around 4 weeks ago bought a 2008 Audi A4 (B8) 2.7TDi with Multitronic box. I found a nice example locally which was fully loaded and came with a full Audi service. The car was very nice to drive, no rattles or knocks and the 40 mile drive home was nice. The car was due a service and after doing some research the gearbox is not a DIY job due to special procedure which is required to change the oil and from reading the forums and speaking to a friend it all said get it done at Audi.

Took it to Audi for the gearbox service collected it the next day, let the car warm up as usual and gave it some boot but noticed a horrible whining noise. My immediate thought was Audi had done a bum job and now something is knackered. Took it back to them explaining whats happened. They have now had the car two weeks. Initially they said I only need to pay 2 hours labour for them to figure out what was up with it anything after that and they would cover it. I said that’s fine but if the problem does turn out to be the gearbox I wont pay a penny and Audi should cover the costs, which they agreed to. They now tell me they have looked at the timing, gearbox and turbo and none of them seem to be the culprit. They say it needs further diagnostic which they will charge me for (they want to attach a number of acoustic sensors around the car and see if they can pinpoint the noise this way). I have refused to pay as I feel its too much of a coincidence they do a gearbox service and immediately after a fault arises. I am also pissed of its been two weeks and they still have no diagnosis! The noise only arises when you put your foot down.

Would appreciate some advice, not sure where I stand on this and what kind of liability Audi has? Anyone suggest what could possibly be wrong with it?

Thanks