3.7 tiptronic box

[Chylam]

Hello all,

I have a 3.7 a8 with an auto box however I have had some problems with it.

When you are in the over run the revs bounce and about 500rpm up and down between 1200-2000 rpm.

Also under light acceleration around 40mph if you press the throttle lightly it will try and downshift and the revs rise and then will try again selects the gear ok then it accelerates.

The second question I have is. I was told by a not very helpful person at a 'gearbox specialist' in Scotland (who I will not name) has told me that reconditioning of the box would cost £4500. Also when I mentioned a replacement from a low mileage used car he stuttered and said that it would not be possible as the mechatronics unit is hard coded to the vehicle and cannot be refitted in another.

I personally believed this was incorrect as I have heard of gearboxes being swapped before. But is this true.

Also does anyone have any recommendations on a place to get the gearbox reconditioned if it gets to that stage?

Many thanks

Matthew