ASU code gearbox is from a Rallye & was made in 2 versions, early type without oilways, & the later type with oilways.
Your full gearbox code indicates you have have early type box which does NOT have the 2 oilway feeds into the transfer box (see photo)
btw all Rallye transfer box casings were made out of cast iron, rather than cast ally of the Passat transfer box
Early type (without oilways suitable for your gearbox) on the right.