Well i'll say this walmart just pulled all of the rotella premium product lines (T 5w40 and DFA) and are now using pennzoil in all of our 5 local walmarts within a hrs drive of here.
there's delvac 1 at ~$19-22 gal or chevron/JD 0,5w-40 is around $12-15 a gallon.
Synthetic as per new ruling is tricky. delvac 1 is a pao and chevron delo 0,5w-40 and the rotella t 5w-40 (came out of 10w-40) which are partial syntheticaly enchanged hydrocarbons. Caterpillar oil is mobil too the regular is 1300 with slightly higher base# and delvac 1 is in silver it's about 3 dollars a gallon cheaper at my local cat dealer.
They SHOULD have better flow at low temp should give better flow and generaly be better especialy since a tractor is simular to road tractor with simular stable rpm and loading so you might expect 3-5% better fuel economy. Kubota's postion is puzzling they claim on the engine the oils aren't any different but then require/specificy the super UDT for all kinds of performance improvements.
Mobil 1 is also a CF rated which i expect would work also since most tractor engines don't realy employ EGR retarded timing or any of the other problems with emmissions onroad equipment uses. you can find alot of info on CH-4 and CI-4 improvements in soot holding etc.. which i assume you'd probaly not extend the oil change interval.
I'd stick with big 3 Mobil,Delvac,shell or if your rich or realy love your tractor go for full synthetic. I personaly switched to all Mobil products they have best oil made.. Delvac 1300, Mobil1 and Delvac 1 the one's that changed the industry about 3 years ago.. I've had about a 25% less makeup oil and around a net improvement of around 1.8% over 2 years with 4 vehicles otr.
I posted in past on info site on jd's of several oil makes and the results maybe do a search?
