The sad part is that this is a personal truck that doesn't tow often. I only tow my boat occasionally. You have been lucky or got a good one. I'm sure they have more trucks running than failing but I personally have never had so many issues with a Duramax. My buddy included.
You pick your poison these days. You could have got a ford and have the cp4 explode, intercooler tube blow out, injector valve seals leak, front cover leak, etc. or you could get a dodge and have the 68 which is junk or let’s say it has the aisin, then you still have issues with front timing cover that leaks, exhaust manifolds that shrink, interior that falls apart and so on.
At the end of the day, all these new truck you basically pick your flavor and deal with the crap they are built out of. Is it upsetting to spend the kind of money they cost and have issues? Yup. Just sucks