"bob b".....On the newer Freightliner chassis' they're having issues with the vent tube on the fan drive. Mine was covered in oil and Freightliner opted o replace it under warranty. Six months later, covered in oil again. I washed it off and extended the vent tube. It was easily reached from the floor cover inside the coach. No more leaks.
With that said, my friend has a 2011 Allegro Bus with the same fan drive, but has a plug where my vent is located????
The plug or vent, which ever you have is on top of the unit, dead center. You can look at your through the engine doors with a flashlight. If you have a vent, spray thoroughly with some degreaser and then inspect after your next trip.
Here is a photo of the vent line:
