Art, you may be right; I sure don't claim to an expert on oils, but the Delo 400 has the SJ rating as well as the CH-4 rating, and it says on the container, "exceeds warranty requirements for all gasoline, diesel, and turbo charged engines" etc. And of course you can get it in a straight 30W although I use the 15W-40 in my tractor. I'm still using Quaker State 10W-40 in my gasoline engines. You know in the early 80s (and I don't know for how long), the Quaker State oil had the CC/CD rating, but dropped their diesel ratings some time ago (I don't know when). I called Quaker State's technical support folks and was told it was just fine to use in a diesel engine, but because of the ash, it should be changed more frequently. Of course, I'm not doing it; I prefer staying with the manufacturer's recommendations, but sometimes manuals get out of date, since Kubota manuals still call for the CC/CD rating and I don't know how you could find such now.
Bird