I currently have a 2010 Silverado just over the powr train by 1000 miles. Took it to the dealer they are talking about replacing rocker arm's the cam shaft, oil pump water pump. They found build up in the case and I think going to try to stick the bill on us. We have given documented proof of regular oil changes. I had been told that I had a lifter arm that was bad hence causing the truck to misfire. I have done some research and saw that there has been problems with the casting. Will they cover this under warranty? It sounds like they may. What years of engine have thsi problem with the casting?