Nope its on the shaft that leaves the main box, that the tfer output seal, on the s2 forum theres a recent thread where they think the gbox breather is getting blocked and forcing the oil into the tfer box, one guy was going to do an experiment with some extra drillings on the selectors.
What I will say is on my s2 with tdi fitted, I drilled and tapped the round tin bit on top of the gearbox and linked it into the rest of the raised breather pipes and have never had any issues with oil migration.
But I do run 85/140 which may help, seriously good oil for series boxes that could have a hard time.