While we're on the subject of trany lube, when I had a VW I was told never to use lube with a GL5 spec. in the gearbox, only GL4. Something about damaging the syncros. GL5 was ok for the dif gears in an automatic. Is the same true for Audi's? In the Bentley manual, it says GL5 for the center and rear difs. It says GL4 for the transaxle, with no explaination why. Barry