Originally Posted By: zeng
Cat HYDO is hydraulic oil, with minimum 900 ppm of zinc.
Cat TO-2 is a an obsolete spec for transmission oil, which could be used as a hydraulic oil.... but may contain VI improvers.
I would use any branded hydraulic oils in AW 46 /AW 68/AW 100 grades.
What about ISO 46 and GL4 are they compatible or old also ? So basically stay away from anything rated for TO-2 because it's the older spec. and anything that states "hydraulic/transmission oil" ? My 2003 manual just says HYDO 10/30, Cat put out a bulletin in 2016 stating new oils, HYDO 10 wt, HYDO 20 wt, and HYDO 30 wt. and states : If a different viscosity is required due to ambient temperatures, the following Caterpillar oils can be used: Cat Diesel Engine oil 10/30 or 15/40. I mean is that basically saying I can throw 5/40 Rotella full synthetic or 15/40 Rotella synthetic blend oil in there ? If I gotta pay the same price, I think I'd rather have synthetic, although they state if using DEO then the fluid change interval should be 2000 hours instead of 6000 ??