GEARBOX Ecu re-placed and still juddering .. Please CAN YOU help me?

I have an audi a6 2002 multitronic petrol.I had the ecu issue and got some diagnostic done by 3 different specialists they all said that the juddering of the gar and the loss of drive every now and than was a gear box ecu. Bought the ecu new from audi got it installed still no improvment apart from the fact that the prnds dont flash as often as before.but the juddering is still there now guys please help me out what coulD that be. The car shows no fault on the diagnostics but still hesitating on pull away and juddering is getting worse iam almost running out of money.. Where do i go??? Does anyone knows if the ecu when bought from audi new is it plug and go type of thing??? Audi just want to eat my money and worse they tech guys dont have a clue what they are talking about... so I am left in the dark please help me....