i know that you can't use Dextron3/mercon in our trannies, just in our power steering. what they do at superlube is use dextron3/mercon and add a friction modifier in it. personally i think it's a bogus idea to do that. they're doing that to save money. i think i am about the 10th person who's had a problem. my friend's f150 started slipping after they did it.