Thanks guys and don't get you drawers in a wad Jim. Just signed on to the board and I did a search with no results for oil. Perhaps I should have done a boolean search. Matter of fact, I'm intimately familar with the oils mentioned as I own a small trucking company. However, synthetics in a big truck is prohibitively expensive despite what the oil companies claim. I'll probably use Delvac Synthetic by Mobil as I've ad extremely good luck with it in the Cummins engines. Look for more dumb questions as I get more into theses MB's. I have three coming in to me.