The other night, I ran across a guy that is a Hot Shot driver with an '04, HO, Auto, Dually, that is completely stock, with 200,000 miles, on it.
He, admittedly, drives the HELL out of it. Often 85-90 mph with a fairly heavy load, on it. Has had it up to 110 mph.
He changes the oil at 15,000 intervals using "quick lube" facilities. He said they use 15-40 oil, usually Quaker State or Pennzoil & whatever filters those stores use.
The turbo on his truck recently blew-up & was replaced & now he is experiencing low power and a steady "haze" of smoke coming from the exhaust pipe, at all speeds.
His old truck ('97 Dodge/Cummins) lasted 779,000 before it was replaced by the '04. His opinion of the new truck is that it is more powerful but, not nearly as good from a longevity standpoint.
It would be interesting to know what is REALLY wrong with his engine.