I have a 2003 Kubota M8200 Narrow tractor and found a hole in the top of the, I'm assuming, transmission case. When sitting in the seat this hole is located between your legs, on the left side of the case, toward the rear. It is not threaded and looks like a hole that a dip stick would go in. There is no dip stick and I'm at my wits end trying to figure out what this hole is for. I wouldn't think it's a vent hole and after looking at every single page of the manual I still can't figure out what is suppose to go there. Any help would be greatly appreciated.