LSJr tests and discusses DexosD babymax oils

[rollins.]

That's correct.
On the other hand—perfectly engineered engine may and will fail if a lower viscosity oil is used, especially in a turbo diesel engine.

It's a good thread and it needs to stay alive. Because nobody had used 0W-20 oil in a turbo diesel engine before and GM just decided to do it.

Europeans have been using them for more than a decade in PC TD's (Volvo VCC RBS0-2AE,MB 229.71,VW 509.00, post-GM Opel/Stellantis OV0401547-A20 etc).

Although field trials with LV HDEOs (ht/hs<3.5cP of various viscosities) started like more than fifteen years ago, OEMs have been really careful and adoption-slow (probably some lower single digit % of all HDEO market share today) .

https://www.petronas.com/media/medi...rst-0w-20-commercial-vechicle-lubricant-media

https://bevo.mercedes-benz-trucks.com/sheet/DTFR_15C140/en

https://www.lubrizol.com/company/specifications/daimler-truck/dtfr-15c140
etc.