Nope, Rotella-T 15-40 has been recommended on this website since I started coming here in '02. Used to be pushed harder on this site than it is now. It's got more zddp than
regular oil, so it's more important for a 2.9 than it is for a 4.0. If 15-40 is too thick for you (I live in Maine and get away with it) you can run whatever oil you like and put in an additive, like from the GM dealership or http://www.zddplus.com/
My bad, i have not seen it that much as i dont spend most of my time on this forum. So would the rotella-t be good for my 2.8? And is it just the rotella-t that has the more zddp, or is that all diesel oil?