Longbox55, that isn't correct. There is absolutely no problem running diesel 15W40 in a gas engine. Too much detergents? Since when did that hurt anything? And the zinc phosphate issue, (ZDDP) is very well-documented. In fact, Hot Rod magazine did an elaborate write up on it.
The zinc was cut out of oil because of pressure from the federal government. With the advent of modern roller cams, which is now on 100% of all new cars, and also because of increasing the life of factory catalytic converters, zinc was eliminated from the oil formulations. This is not snake oil. If you don't believe it, a very brief internet search will educate you on it.
But do what you like. It's your truck and it's your choice. No one's twisting your arm one way or the other.
