Multitronic groaning at low rpm

[Murphm02]

Hi all, 

I have a 2012 Audi A4 B8 se with a multitronic box. It has the 8 speed box. The car has done 90000 miles. 

Recently it has started a groaning noise when driving and the engine rpm drops too 1000rmp or in the lower gears. 

When driving if I pull off slowly the car makes an occasional groaning sound and as engine rpm increases it goes away. Also when driving and I come to a stop and take off again quick it will make the groan sometimes. But If I accelerate fast there is no noise. 

Intiial thoughts from the mechanics at the main dealer were it was a water pump. Had the timing kit done and no improvements. The dealer is claiming its fine now. 

Anybody have any experiences with the above. As i am having little trust in the dealer on this occasion 

Thanks