I have a 665 DTC. The manual calls for 80w90 ep (extreme pressure). It is available at Tractor Supply for $70/5 gallon, also at Carquest for a little more.
Maybe you can help me. I want to replace the hydraulic control value for my loader. What would be the proper fluid flow per minute required for a 60-hp tractor?
Here is the page out of the Service Manual. I thought that sounded really heavy, also. I usually use the Premium Hydraulic oil at Tractor Supply, but the 80w90 EP is the stuff to use in my tractor.
These model Farmtracs are Ford. Ford tractors were made by Fiat, Shirbaura, Escort and I am sure several others. The older tractors were all Fords. Then came the Fordson (I think that was a Ferguson/Ford Combo). If I have my facts right Ford quit making tractors in 1992, but the name carried on with Ford New Holland. Then prior manufacturers of the Fords rebranded them on the Ford design. LS is another one that used the Ford/New Holland design.