I asked the fellers who worked at Cummins who were putting a new transfer pump on my pickup, what they thought about the new bio diesel, and they didn't think that they had heard much good. Thought Cummins might not honor the warranty if anything went wrong, but I don't see how they could tell it was used unless there was some in the fuel tank when it was taken to the shop. I would like to know more about it. The bio diesel that is. Anybody tried it?