you need to be sure what goes in is the right stuff, audi box and diff oil is expensive, there are alternatives though Redline, Motul, Millers just to name a few. Based on experience even the correct oil weight in a different brand can cause a heavy gear change until the oil is warm. Back in the day a long time ago i used Castrol Taf-X in my old quattro's and that was perfect, it may not now be compatible with the newer boxes.How many miles has the car covered?
