Prevost fan drive oil?

[PP]

I'm getting ready to make another move down the road and checking the fluids when I notice a small drop of oil on the top of the muffler. It came from the fan drive housing vent. Not sure why it spit up this time, but I opened the fill plug and checked the level and then began wondering just what kind of lube is in this thing. Is it regular 80W differential oil? It does look like a small differential the way it turns the power to the blades at a 90° angle. It's not low at this point, but would like to add the type to my personal manual. Thanks in advance, Will

Okay, I went to the Prevost forum and found my answer. Synthetic 75/90W oil changed every 50K miles.