I found your X485 manual on-line at JD website.
"NOTE: Machine is filled with John Deere Low Viscosity HY-GARD® (J20D) transmission oil at the factory. DO NOT mix oils.
These machines are equipped with a internal wet disc brake transmission. Use only Low Viscosity HY-GARD (J20D) transmission oil. DO NOT use type "F" automatic transmission fluid.
IMPORTANT: Avoid damage! Use John Deere Low Viscosity HY-GARD (J20D) transmission oil to reduce transmission noise and to increase response time for the hydraulics and power steering.
John Deere Low Viscosity HY-GARD (J20D) transmission oil is specially formulated to provide maximum protection against mechanical wear, corrosion, and foaming."
It is the same with Kubota. They have a SUPER UDT or a regular UDT hydro fluid. One is Low Visc. the other is 'regular'.