I know CAT and Hydra Oil come from the same company, however I believe the spec may be different. I also think Hypro oil is from the same company and I wouldn't be shocked if General was the same thing dyed a different color as well.
In fact, in our warehouse the other day we opened a Hypro, CAT, and Hydracell oil and by eye couldn't see any noticeable difference. I was told 30 weight non-detergent oil is perfectly fine for use in
CAT pumps. Is CAT oil one of your biggest expenses? I'd think there were a lot of places I would be looking to shave costs before that. I know it's more the point that no one likes to fell screwed over on a purchase, but understand that none of us selling CAT oil are making any money on it.
Ron