I am on a long trip in my '96 Dodge with a Cummins 12-valve engine. I will need to have my oil changed while I am away from home. I usually use Valvoline Premium Blue, but have not been able to find it while I'm on the road. Is there another comparable oil that I can use? I have heard that Walmart has an oil that would be good, but I can't remember which one it is. I have brought my own Fleet Guard oil filters with me in anticipation of having my oil changed, but I need to know what oil would be a good substitute for the Premium Blue. I am pulling my 12,000 trailer from coast to coast and want to make sure I am using good oil in the truck.