I am wondering if anyone can offer any advice on diy front differential fluid change on a 00 avant quat. It uses the V tranny meaning the front and center differential share the same fluid. I have searched the board but have found no advice. I also own a Bentley manual which in this case is rather vague. I can't seem to find an easy access point. Has anyone done this themselves? I know Audi says its a lifetime fill, but since I changed the rear diff fluid, the tranny fluid, I might as well go all out againt Audi's advice and change the front/center diff fluid as well.

The car has 115k.