I have used Chevron Delo 400 15W-40 in all my Cummins diesels over the years, both 12 valve and 24 valve, summer and winter. No problems to date.
My current truck has 409,000+ miles.
I use NAPA Gold oil and air filters (Wix)
I did find, a couple of years ago, that in the fall it pays to run the fuel tank well below half full, then fill with Winter Blend fuel. Near zero temps with summer fuel means you probably won't be going anywhere until it warms up!
CM1, USN (RET)
2017 Jayco TT
Daily Driver: '14 Subaru Outback
1998 Dodge QC LWB, Cummins, 5 speed, 4X2
2 Kawasaki Brute Force 750 ATVs.
Pride Raptor 3 wheeled off-road capable mobility scooter
"When seconds count, help is only minutes away!"