I bought a SpeeCo branded log splitter yesterday. It came with 5 gallons of AW46, but once the entire system filled up, it's about an inch below the add mark on the dipstick and 1.5 gallons low. I'm seeing mixed reviews online that don't seem to match what's in my owners manual. People say their manual specifically says not to mix whereas mine says it can be "substituted" ( I take this to mean it's mixable?) as well an an entire switch for cold weather performance. Are there any long term issues with me topping off the system with ATF? I have plenty of that on hand.