Perhaps I'm wrong, but I thought the Cummins held 14 qts? Not that it matters a whole lot for the purpose of this thread ...
That's a fair deal for the OCI. Is that a "final" cost, or are they going to add shop fees, taxes, etc onto it? Not that it's a bad deal, but just would be interested to know where the "true" cost would fall out at.
On topic, I'm not actually sure who makes the Mopar diesel oil. Cummins is typically paired up with Valvoline, but that does not mean Chrysler is doing the same. However, I would be remiss if I didn't point out that your sense of this being important is probably way greater than the reality. As long as they are using a certified CJ-4 lube, it would be just fine.
When I type in "Mopar", I get two choices; one for Chrysler of Canada and one for the Corp, presumably in the US. Oddly, it is only the Canadian link that has 15w-40 lube listed ... Take that for what it's worth. I highly suspect the Chrysler lube they offer is certified, but we may just struggle to know what specific link it's listed under. I have found that the API EOLCS can be finicky at times; you have to know the EXACT way they entered the info to find what you seek. As an example, the Walmart products for the US are under "Wal*mart" but the Canadian is listed as "Wal-Mart" ... note the difference in the asterisk and hyphen. And you will find neither if you type in "Walmart" with no special character. So my point is that you may have to tinker with the API search tool, after you first go find out the exact name of the product the dealership is offering.
https://engineoil.api.org/Directory/EolcsSearch
Admittedly, this will only show you if it's licensed; it won't tell you who makes it. But I contend who makes it is moot anyway. You may care, but your engine won't in the slightest.
