kubota m8950

Looking for something to pull a 15' mower to cut some fields. Found this. Hours: 2,450 according to the tach Year (??) Maybe 1990? (I have no clue) Drove it yesterday with a 15' Rhino behind it and cut some 3-4 foot tall junk in his fields.....almost exactly what I'll be cutting here. Did...

Just noticed when in 4wd a noise is coming from the crown and pinion area. Anyone have any ideas of what it could be? It sounds like its running dry somewhere, have checked oil/grease etc can't see anything wrong....:confused: