What kind of differential fluid should be used in an Audi 80?

I am planning on changing the differential fluid in my Audi 80 and I'm not sure what type to use. I have read conflicting information online. Can someone please provide specific and reliable information on the correct differential fluid for an Audi 80?

The recommended differential fluid for an Audi 80 is a fully synthetic 75W90 gear oil. This is the same fluid used in most modern vehicles and provides the best performance for the differential.

It is important to only use fluid that meets the specifications set by Audi. The manufacturer recommends using their own branded gear oil, which can be purchased at any Audi dealership.