Ok I've dont a bit of research I am planning on going with oil filter
ACDelco PF2232 which I think actually came on it new? and going with shell rotella 15w40 "NON" synthetic... I went to shell rotellas site they have triple protection etc...and syn....

is the shell rotella T 15w40 the "non" syn? I believe so and this is what I plan to use.. any good or bad info on it?

thanks for any input and I change my oil 3,000-3,500 miles

That oil is pretty good, alot seem to like it. That is what I use, and have no problems. Those that have done an oil annalyis might be able to help even more. As for the filter I have always used ACdelco on everything I have owned. However on my DMAX I use Hastings and don't have a problem with them, I feel that the AC would be fine. Also I think you could lengthen your intervals, most on here seem to go atleast 5000 miles and some go as much as 10000 miles.

Must different on newer dmax's, cuz my oil change light seems to come on pretty close to 3k, and my oil life readout is at 65%..I change at 3k anyways, using Delo, but that might change as per my post re: how's your oil look..

Rotella T 15w40 dino is as good a non synth. oil as any other for your Dmax. I've used it all along. I also always use AC 2232. I'd think about going to 5k to 7.5k on the oil change.

I have allways used Rotella in deisel trucks and never had any problems. After the first couple oil changes I change at 5K no matter what. I use the ACDelco filter also. My Duramax came with GM filters exept the air. My buddies 8.1 came with all ACDelco filters.

Mobil Delvac 1300 Super Motor Oil 15W-40.

I'm using the exact stuff you plan on using...PF 2232 and Rotella 15w40 T. However, IMHO, 3/3500 is way too often to change oil...check the DIC.

alright thanks for the tips guys

mobil delvac 1300 super motor oil 15w-40.
x2

Vavloline Premium Blue Extreem fully synthetic. I did my oil and rear diff at 2500 miles.

My mileage dramatically improved at around 5500-6000 miles.

I'm planning on towing a 14K fifth wheel across the US into Alaska next year. I would like to run synthetic but all the 15W-40 are dino oils. Any suggestions?

I switched to Schaeffers 9000 Supreme 5w40. This extended my change interval according to Blackstone Oil Analysis. I change it around 7500 miles but the analysis shows it can go way past that mileage.