Dave, have you had the upgrade to the EGR system and the oil cooler system done? What year is it?
I'm guessing it doesn't have the upgrade done, Greg. This was my dad's truck so I've only had it for a little over a year now but I doubt he had it done. It's an 06 btw.
The oil cooler set-up blew on mine at 150,000. The EGR cooler blew about 2000 miles later. $12,000 repair bill. Total top end rebuild.
Mine was an '05.