(quoted from post at 21:18:53 02/06/15) I just helped a friend of mine add a 843 loader to his 4650. Used a JD Joystick for it. I have a 4250 with a 280 loader and have done a total of 3 of them now exactly the same. All you do is get a power beyond plate, which gives you flow (and return) to the remote valve. I would look around for a used one. I was certian Larry was advertising one for sale not long ago. Might save you a few bucks if you can find one.
For the actual valve setup, I like to stick with deere products because some of the aftermarket valves and such kinda scare me a bit. The joystick kit is all you really need and is still available thru deere. And thankfully so because not everyone drives a 8000R series tractor with plug and play electronics.
Anyhow the valve we used is a [b:488b07c213]BW13247[/b:488b07c213]. This is the 2-function valve. They do offer a 3 function if you plan to run a grapple or you can just run the grapple off a remote as well. This kit has just about everything except the hoses that run from you power beyond plate to the valve. You can get those fabricated yourself once you know how long to make them. It runs just over a grand brand new, which is not terrible considering how nice it works and all the parts are available thru JD. Just remember it does make a difference which port is pressure and which one is relief on the valve. I can advise if needed.
Here's how it looks in the cab. Would be similar even if you had a open station.
Here's how the valve looks and mounts. Two very short 1/2" carriage bolts will bolt it to the battery box with existing holes (no drilling req'd)
I splurged and added a foot throttle to my tractor. You would not believe how handy this is. I guess if you are used to a 3020/4020 then you can imagine. Why they didn't make these standard on 30-60 series I don't know. But when you have your hands full with the joystick, it's nice to be able to goose it without letting go.