That's a big tractor. Ford 7.5 straight 6 diesel correct? Why would you use that oil when there are so many HDEO oils available. Ford seems to want 15w40, 10w30 and 5w30 based mostly on climate. I would use Valvoline 8600es or similar. Easier on the wallet and more correct for the equipment.
But I agree with kschachn, I don't think you will be back.