Our Bobcat dealer recently moved away, leaving the nearest dealer 4 hrs drive from me. Before they left I asked the parts guy if I could use a substitute oil for the Bobcat brand hydraulic oil and he replied that I definitely could and that it was simply an ISO 46 tractor hydraulic fluid. So, I went to our Chevron dealer and was told that iso 46 and tractor hydraulic fluid are two different animals entirely and that he personally uses Chevron's THF 1000 in his Bobcat. My question is which is the correct oil to use, an iso 46 hydraulic oil, or a tractor hydraulic fluid (Chevron THF 1000)?