Problem Tiptronic automatic box


hello....I have a problem related to the car gearbox...more specifically, an Audi A3 from 2002 engine 1.8 t -180 hp-AUQ tiptronic automatic gearbox! I bought the car about 8 months ago...I drove about 15,000 km without experiencing any problems with the gearbox..a few days ago...the gearbox started jerking when changing gears...specifically gears 2 -3 3-4 ...I went with the car for diagnosis and the box does not have any errors stored! does anyone have any idea what the problem could be