I have to agree with Amsoil working great. Other stuff may work just as well, I just don't have any experience with it. I did the first 1/3 at 30K miles and what came out looked like crude oil, and like ATF it was nasty smelliing. Each 30k later it was more red each time. Not sure of what % of the factory fill is left but Now I'm going to do it every 45K Cheap insurance.