Need to top off the big tank up by the fuel tank. Cat has fluid for 100$$ per 5 gallons, plus tax. I hear it's made by Mobil. Does anyone know what to ask for in a Mobil product? What do the 953C owners on the forum use? I'm not against getting the best but don't know if Cat is any better than something else that may be exact same product for a better price. LB