These tractors are easy to hook up extra vales to, also known as power beyond. I've found the easiest way is to get a T with a female on one side and 2 males. White called this part # 939951 in the books. Take the hose off that comes from the valve body below, right in front of the left three point lift arm. In my picture, it is on my 4-225, as it was easier to get a picture of. The existing hoses are lined in green, and the new T and hose are red. Put the T in there and run your hose to your loader valve from there. Like John mentioned, the loader valve needs to be closed center. Then take your return oil from that valve and route it to the back of the hydraulic housing. There should be a pipe plug on the lower left, just above where the three point housing meets the transmission housing. I'd drain the oil out of the system before removing this plug, as it is below the oil level in the reservoir. Attach your return oil hose there, and you should be all set. In my second picture you should be able to see where I have a yellow handled needle valve to shut off hydraulic flow, with a female Pioneer coupler attached to that. Just to the right of that is a male Pioneer tip that goes into the reservoir. That's where the return line goes.