I like Mobil 1 gold cap best, but it got too expensive, so now I use Mobil 1 grey cap. Way cheaper, and I just change the oil more often. I tried Rotella T, but didn't like that is always looked dirty, even when fresh. My tranny seems to shift the smoothest on Mobil 1 gold cap, but the silver cap is a close second. It was knotchy with the T.