I have tried Lubeguard. It has the same consistency as ATF and looks like ATF. (they make a gear oil additive as well) Literature impressive, suppposed to replace Sperm Whale oil which they claim was in transmission fluid in the early days prior to the crackdown on whaling activities. Anyway, they show these scientists etc. but like most of these additive companies when you try to see who actually did the independent lab work they fail to mention the name of the lab. Anyway, I believe that if you maintained your component (engine or transmission) and it is operating fine no additive will make any difference. As such lubeguard did nothing for me. (still in tranny) I used synthetic ATF since 25,000 miles on the car anyway. If you need something as a last resort due to a problem then try it. If operating fine, save your money, it will not do preventative maintenance in my opinion.