I know someone who changed his trans fluid from stock in his 2001 mustang GT to I believe a 75W90. I think the stock runs 75W140 or 120. We used Torco and I wanted to know how many people heard of Torco. I'm thinking of doing the same thing for my 05 mustang GT cuz his shifting is butter smooth now. It seems too good to be true but I wanted to hear if there are any "Don't do it cuz you'll kill your 05" warnings. Thanks so much, and if it sounds safe, I'll let you guys know what improvement I get in shifting.