The hydraulic system requires specific fluid, I follow Deere's recommendations. I use John Deere Low Viscosity Hy-Gard, Part# TY22000 in gallon containers. I have it in five gallon pails but can't access the part number at present.
I service quite a few vehicles and need the convenience of bulk lube products. I use an All Purpose HD Fleet Oil, 15W-40 for all my vehicles. I purchase it in 55 gallon drums from my local NAPA store, it's Valvoline Supreme HD in NAPA's wrap. I researched the specs and it shows up as meeting/exceeding a bunch of mfgr's requirements, including Deere, Case/IH, Cat, Cummins, Ford, GM, Benz, etc.
When in doubt, do what Roger says, follow Deere's advice, it's not worth a big problem and you will always know you're using the correct product for your tractor. Cost is not the object.