After 5 or 7 minutes of driving from a cold start, this Mobil 1 Synthetic ATF makes glass-smooth shifts inside my '06 Camry. I like the Mobil 1 and might increase it to 100 percent of the ATF fluid. (Right now the car has 50 percent T-IV and 50 percent Mobil 1, as of two weeks ago.) I'm a little concerned, though. In the first 5 or 7 minutes after a cold start, the shifts aren't so glass-smooth. On occasion you can feel the shifts jerk just a very little bit. I really can't compare this shifting to the last 3.5 years when I had 100-percent T-IV ATF in the car, because I really never paid attention to the shifting until this month, when I first drained and filled with Mobil 1 ATF. Again, I only started paying attention to the shifting this month--kinda funny, eh? Is this occasional slight sensation normal for Mobil 1 in the first 5 or 7 minutes after a cold start? I'm not even sure jerk is the right word for it--may be too strong a word. But after the first 5 or 7 mintues, shifts are glass smooth. The car has 25,000 miles on it. I'm not sure to flush and fill next time with Mobil 1 or T-IV, but I'm definitely going to flush it soon to remove the remaining 50 percent factory fill.