As for 4 engines in less than two years being bad work ect, I think my issue is more because the truck is an F450 with a box. So the truck is heavy 100% of the time unlike a pickup. My truck always weighs 18,000 pounds or more. Most 6.4 dont see this kind of workload 100% of the time. My truck has never been over its limits but is close to them all the time and that is why I see the problem so much more frequent than most..
That's odd my f550 is only rated at 19,500lbs. Aren't f450's rated around 15,000lbs?