My Cummins 11 Litre M-11 has 50,000miles. Is there ANY advantage to 'blending' some Rotella Synthetic with the 15W-40 I now use?...Say maybe 20%Syn and 80%mineral oil 15W-40? Locomotiveman
Thinking of Mobil 1 Synthetic in my Dana/Spicer Motorhome Diff. w/32K Gross weight and Cummins 11 Liter engine. Why would one choose 90 weight over 140? Simply better when cold? Or am I missin' something? Locomotiveman