The new Cummins oil requirements

[Danny Phillips]

The Chrysler Ram dealership here in Payson uses Shell Rotella 15/50 That's what I've been using since new, even in Washington state it was the same.

 

[06 Dodge]

The Chrysler Ram dealership here in Payson uses Shell Rotella 15/50 That's what I've been using since new, even in Washington state it was the same.

IIRC it was the 2019 and newer engines that require 10w oil older due to change over to roller lifters, the older engines with solid lifters can still use 15w oil.