I have a neighbor that has a John Deere 430 Garden Tractor, Diesel. I am trying to help her with tractor service. The hyd. fluid is low. There is a sight glass in the hyd. line at the rear axle. The manual states the transmission oil is a Deere all weather hydrostatic fulid or type F auto transmission and it does not state what the hyd. oil is. I think this is the same thing? Is there only one resivor on this tractor for both?