That engine actually has a very good reputation in medium duty truck applications, the problems it's been having in Ford trucks is because of changes Ford made to it after it was out of Navistar's hands. The 5. 9 Cummins is probably a more reliable engine than the 6. 0 and there's no doubt it's a better work engine but even the good old 5. 9 has had it's share of troubles over the years and overall International's diesel engines have always been at the top of their class, I'd trade my 5. 9 for a DTI-466 in a heartbeat if I could.