There is no licensed 5w-40 for Mopar in the API index:
https://engineoil.api.org/Directory/EolcsResultsDetail?accountId=-1&companyId=10112&resultsUrl=%2FDirectory%2FEolcsResults%3FaccountId%3D-1%26brandName%3Dmopar
There was some internet chatter (some of which you were involved in) that it might be a Euro spec 5w-40. Here is the PUP link for their Euro 5w-40 ...
http://www.pennzoil.com/en_us/products/f...c_Motor_Oil.pdf
As you can see in the PDS for this lube, it meets the spec (MS 10850) that is for Chrysler. The only diesel rating I see on this Euro spec product is for "CF" and nothing more. That is NOT appropriate for your Cummins.
I was also able to locate this: (admittedly from the end of 2014, but there's good info there!)
http://www.moparinternational.com/assets/maintenance/english/pdf/Cross_Reference_Guide_19Dec2014.pdf
It's a list of all the Mopar part numbers and their specs!
If you look at the ONLY 5w-40 rated lubes on the list, they are for gas engines and the small older Jeep diesel 2.8L.
The only diesel rated lubes for your Cummins (CJ) on the list here are the 15w40 lubes.
I suspect there may be an updated list of these products, and it likely would have CK-4 as well, but because this is from 2014, it won't be on this particular sheet.
Here is the official Mopar International site for the lubes; 5w-40
http://www.moparinternational.com/maintenance-catalog/action/guide/ENGINE OILS/68231020GA/
Look at the applications; it is NOT for the Cummins!
This most probably is a case that a service guy saw a vis grade (5w-40) and grabbed the first one that he found, despite it not being a diesel oil for your Cummins! It is approved for the little diesel in the Jeep; the old one. But
I doubt it's approved for your Cummins; I cannot prove it, but I highly suspect it. I think I'd go back and ask to see a lot more proof, and probably not have them service it any longer. By all means, keep all receipts so that
IF something goes wrong with the engine due to lube related issues, you've got proof it was not your mistake, but theirs.
There is no reason for you to even need a 5w-40 in TX; specifically ask for the Mopar 15w40, which is diesel rated for your 6.7L Cummins and approved by the API.
Summary:
- It appears that there is no 5w-40 rated diesel Mopar oil for your Cummins, only 15w40.
- They have put a gasser oil (and inappropriate diesel application) in your Cummins.
- They are idiots; run away from the dealer (you may return to chastise them and give them "what for", but they are clearly more interested in turning quick sales than spending time getting things correct). You were right to not have any confidence in them!
- Get that stuff out of your crankcase ASAP. While I don't think it will implode at the next stoplight, there's no sense risking it.