They love to be used as engineered. Haul,carry a camper or tow. They love to work.Hello,I have a 2006 Cummins 5.9. It’s stock besides a lift kit and I needed injectors at 104K. Currently at 133K. My question is,how can kids put tuners on these things and beat the crap out of them and nothing happen,I religiously maintain mine and don’t drive it hard at all. (I get it up to temp). At my work place there’s lots of diesels started cold and ran hard. Why is mine,if I hit a quarter in the road somethings wrong yet everyone else has no problems?