Moin, I would like to put my recent experience on the grid on the above-mentioned topic. First of all the vehicle details: mileage 136,500 km, vehicle age 9.5 years (FL), all-wheel drive Haldex 5th generation. For a long time I had an unusual noise after driving off, reaching about 50/60 km/h, which came from the rear right. It sounded like a short “jabbering/sighing” – technically speaking like a short relaxation of a pump. Two weeks ago the Sit escalated. uation: Now this sound appeared longer, louder and already when starting up. Notable, the larger the steering impact when driving off, the louder the “joy”. After a short search in the net I tapped on the Haldex clutch. Here especially on the oil pump installed at the rear right and the oil filter there. Before I could realize an appointment at Audi Service, this noise suddenly did not occur. Nevertheless, I noticed the appointment. The service consultant said lapidar: If he can’t hear the sound, he doesn’t do anything. After making sure that I bear all the costs, I could convince him that he was reading out the fault memory, dismantling the Haldex pump (two screws) and controlling the oil filter there (seven). And look – filter was completely closed! That is, the pump has always had to work against the obviously extreme counterpressure of the contaminated filter. Screen was cleaned and new oil was refilled. Costs 350 EUR. And no, I ha be never pulled a trailer at the trailer coupling during the entire mileage and have never been in the field with the car. I also kept the maintenance intervals (every three years) but only new oil is refilled there. According to the manufacturer, the filter is not a control or maintenance point. I.e. also my Q3 has received three new Haldex oil, but the filter has never been cleaned. So, consider for a possible upcoming Haldex oil change during your drive It is easy to avoid possible more costly consequential damage (pump, lamella coupling etc.). In the net there are a lot of videos on this topic…….. Greetings. Brake66