Have a 2011 versatile 575 with a cummins QSX15 and a versatile 305 MFWD with a cummins QSC 8.3 both Tier 3 engines. Have been using CaseIH No.1 15w40 but was thinking of switching to Mobil delvac 1300super 15w40 to simply things(use mobil trans and hydraulic fluid). Trying to wrap my gray matter around all the specs and getting frustrated. Case is Vicosity oil company and their specs seem as good or better than mobil. Maybe I'm off base. Guess I'm looking for some opinions from people in the know.