Manual says not to use CJ-4 oil

[Farmer495]

The Owners manual for a Kubota RTV-x900 (diesel) says:

"The CJ-4 engine oil is intended for DPF (Diesel Particulate Filter) type engines, and cannot be used on this vehicle."

I've been using Rotella T4 for all my diesels which says meets CK-4, CJ-4, CJ-4plus, CI-4, CH-4. So does this mean I need to use a different oil for the RTV that does not specify CJ-4? Or, does Kubota mean only those oils that meet only CJ-4 are not to be used?

(Dealer is closed at the moment so I won't get to ask him until next week.)

My manual for an M series has the same wording.

I buy Kubota branded oil from Kubota dealer that sold the tractor new, rating is CK-4 and also has CJ-4 CI-4 etc etc etc on the label.

 

[RickB]

Some early CJ-4 oils were not backwards compatible. I remember that was an issue with New Holland Ambra 15w-40 when their CJ-4 was introduced. What we have here I believe is another case of oil technology outrunning published info in operators manuals. Clearly Kubota 15w-40 is now rated to replace and supersede prior standards as are countless others.
You are buying oil in 2021 and reading a manual that could have been written in 2012 or 2013. The CJ-4 standard dates back to 2006.