Yep, ATF seems to thicken up like molasses in January up here. When the ambient temp hovers around 10F all day, and I start up my beast for the commute home, the tranny not only takes another second or so to engage when you put it in gear, but even then, when you first apply some throttle, there's a very noticable delay before the vehicle actually moves. These changes seem to improve (though are still noticable) since the switch to Mobil 1. Does it translate to less wear/longer transmission life? Don't know (yet) but I figure it's worthwhile to stack the deck in my favor.