I meant to qualify that and ask if running the 15W-40 in my truck engine during the NE winter is a bad idea. Too think still?

I personally think that running the 15-40w synthetic or blended oils in the truck 8.1L (496) engine is the best choice in any climate, especially warm climates. I just don't like what I see in these engines when running the 5-30W and 10-30W.
I think the higher oil consumptions that show up in the trucks are partially attributable to the lighter oils in this particular engine.
Just my opinion though.

Best Regards,
Ray @ Raylar