Sounder, Bink is my B-I-L and a first time tractor owner. I helped him find this unit. It is a light industrial with NO hydraulics other than the external hydraulics that power the loader. In other words, the seat sits on an empty sump. The loader fluid is in a separate tank mounted behind the seat. No 3ph or PTO on this one.
So, in this case I don't think it would matter much if he wanted to put 80W-90 gear oil in the trans and diffy since I assume the pto hole between the sumps is blocked off somehow. Plus if any did leak into that empty cavern, it wouldn't hurt anything.