I'm surprised they did the same BS with the new trucks that they did with the first '14+ with MS-11106 then decided that CJ4 oil was the 'right' oil to use later on.
MS-11106 is a 5W-30 LS Euro oil.
Invariably, they have a similar HTHS to Rotella (3.5-3.7), and a higher HTFS - so the concept that the change was for film strength as outlined to the government was a lie, predicated on the fact that admitting the issue was a torsional vibration failure would have cost them $$$$$$!
The CJ-4 was used because it has a high KV100, and increases the weight of the crankshaft assembly in practical use due to a heavier Windage cloud - and that alters the frequency at which the failure occurs.
The current spec is an A3/B4 ACEA oil - not necessarily low ash - but as @biodiesel
can attest - these oils are significantly more robust than a CJ/CK diesel oil - there’s maybe 2 oils on the whole list that would provide worse wear protection than T6, and the vast majority would exceed everything except Delo… while having an HTHS that would probably give a 6-10% improvement in economy over that specific oil! Several provide superior wear protection to any shelf CJ/CK options, and some specialty oils! Heck, even the Pennzoil option is relatively solid!