Many of the newer owners manuals for ATV's are recommending against using diesel oil. Does anyone know why this is? I probably know of over 100K miles being put on atv's that all use HDEO's. It is very common. Im just wondering if the newer ones maybe have some gold metals that are sensitive to HDEO or if its just a ploy for them to sell there own labled oils. Im running Delo 400 LE in both my Grizzlys now and one has 4700 miles on it almost all of them with Rotella 15w40.