The prior post that had the emails from FCA to the EPA stated that FCA thinks (assumes or evidence based?) that the main bearings fail due to oil viscosity. Solution (or guess) was to change from 5w30 to 5w40 oil. What other engines have you ever heard of being that picky on oil viscosity? How did the engine ever pass lab testing with the 5w30 oil if the problem is the oil? Forum evidence of some owners still using 5w30 without failure and new trucks with correct 5w40 having failure tells me that FCA took a guess that the problem was oil. Or at the very least FCA calculated that thicker 5w40 oil would mitigate some of the failures until after warranty time.What the hell is going on with these engines? How does an engine make it to 47,000 miles with an underlying manufacturer defect? It seems like it would have blown a long time ago. There is definitely something that FCA knows about our trucks/engines that we don't considering they completely redesigned Gen3 engines.