Just picked up a rib of Chevron delo 400 multi grade for my 02 duramax. Fits all the requirements for that engine. I'm wondering if I can safely run this in my John deere 4120. The api ratings for the 4120 call for CJ and higher. According to deere that would be JD 50plusII branded oil. What I read stated that this oil was to be used in engines with DPF systems which my engine has none of. So I'm thinking that since tractors did not come out with DPF systems untill 13 that maybe deere was just adopting the higher rated oil sooner? What do you think. Is multi grade ok to use?