I have a 1988 Bobcat 743. Currentky it has bobcat hydrostatic fluid in it. Is it safe to mix other hydraulic fluid with bobcat fluid? The dealer is 50 miles away, I would like to buy something locally that I can add to it. I read in another post that I should use ISO 46 Hydraulic oil. I just want to be sure I don't screw anything else up, I already have to find another tilt cylinder SO I am trying to be careful. Any advice would help.