I changed out the FF at 3k miles in my 2010 Ranger and replaced it with the Amsoil ATF. Not that it was shifting bad or anything like that, just wanted to get the initial wear out of it. I can say the thing shifts smoother with the Amsoil ATF in it though. Also did the rear at the same time and used the Amsoil Severe Gear 75W-90, again, just to remove the initial wear.