I was traveling at 63 mph rpm around 1500. I was shocked when I first looked at def guage and it was at 3/4 wow that was after 400-500 miles. I guess from comments that maybe normal I'll see what dealer says today. As for,the brand of def the dealer says that some cheap brands "Walmart can cause damage. There have been comments on Ram forum that users of Walmart def have caused problems, vehicle shut down tow to dealer and had to have system flushed out? I'll stay with molar for now.