Found this on the web, which looks like what VW uses for factory fills - http://no.servicebooking.net/castrol/lubetable/volkswagen_retail.asp?lang=no
Looks like they used 0/5w-40 almost exclusively for engines.
Today I looked at a bottle of gear oil for my Passat (G 052 911 A1) at the dealership and it looks just like the pictures on the web of Castrol's TAF-X. It was .5 liters and $24. The G50 (G 005 000) oil which has been around for a while was only $21 for a quart and looks like a bargin compared to the new stuff. I'm guessing it has some of the same ester's that's in GC as I read somewhere on the web that it's a polymer free gear oil. VW is calling it a lifetime oil with no schedualed changes, on topping off. It's viscosity spread is 73/14.4 @ 40/100 degrees which is pretty wide and has a VI of 206, if I remember right.