I just changed my oil last night in my 2008 silverado with 22,000 miles, which has ran nothing but PP 5w30 since about the 4,000 mile mark, with shorter change intervals due to break-in....I want to run this next interval as long as I possibly/safely can and then do a UOA including TBN. Im just wondering what is the longest anyone on this forum has run this oil? What was your TBN? I hope my grammar, and punctuation are correct? The last time I made a post using too many periods.............................................................................to end a sentence, the grammar police got worried. -Ponch