Tiptronic 4th to 3rd

[t11tmm]

Hi I'm looking for some advice...

A6 2005 3.0TDI Quattro Tiptronic 73K

My Transmision has recently developed a strange niggle..

With no throttle on (coasting) as the box shifts down from 4th to 3rd there is a very slight and short vibration which appears to be coming from the rear drive.

Its also not quite as smooth 4th - 3rd than the other shifts.

As I am new to this car and box I'm also wondering about some other "strangness" in 3rd.. where by sometimes when shifting down to third it will keep the revs up to 2-2.5k then drop right down and get full drive power without a change in the throttle position.
Its almost as if there is another gear in there..!

The issue appear's not to be in anyway serious, its just a bit of a niggle.

So wondering if any of you can offer advise....

[a8 tech]

Best bet have the gear box re-adapted this entails the dealer connecting vas 5051/2 or even vag com and resetting the gear selection and throttle body sometimes this resolve this kind of complaint also the term fuzzy logic applies to this gearbox and this means over time the gear changes adapt to the driving style so if the main driver drives casually then a second infrequent driver uses the car and hammers it then the main driver uses the car again the gear change can vary until it once again relearns the main drivers style