Being as the dealers were instructed to drain the 5w30 and put 5w40 in the 2016's they had on hand, I went with changing my 5w30 to the new spec 5w40 oil ASAP!
I used up the last of my Pennzoil 5w30 and, yesterday, I went with a new filter and Rotella T6. Only had 3000 miles since the last oil change but decided to go with the new spec. I previously used Rotella 5w40 in our MH diesel engine and, when we bought our JGC, I was used to diesels running 5w40 but thought that VM/FCA knew better going with a 5w30. Well, obviously not