Those of you piloting a Cummins powered 19 Ram may or may not have wondered what the factory engine oil fill is - I did. You may also have noted that the owner’s manual is specifying a 10W-30 (meeting appropriate specs) as a recommended engine lubricant. While a 10W-30 oil grade is not unusual in the diesel world, it is a departure for FCA to be recommending it for the Cummins equipped Rams. I spent a fair bit of time trying to dig up some background on the switch and every FCA individual (dealer and FCA CS) I spoke with re the issue were ignorant of the fact that FCA had made the switch. Most insisted it was either 15W-40 or 5W-40. This much I know (or think I know): Factory fill is assuredly a Shell product and probably Rotella T4 or T5 (I suspect T5). Please chime in if you think or know otherwise.