quit running

The biggest concern I recall from way back in late 2002/early 2003 from when the 6.0L was launched was a stall and no start condition due to a relay box issue. There is a 10 amp power fuse at the relay box at the back of the engine compartment on the drivers side that has a wiring issue. Tap on the box, and move around the relays and fuses and your truck may indeed start. If so, repair the circuit. This would also be consistant with a P0605 or similar PCM / FICM / TCM power/memory code, if that's what you had. However, it is 8 years later now, and many other possible causes exist for your concern as well. A GOOD solid 6.0L experienced technician would easily be able to determine your failure. Finding one may be initially challenging, but with a little effort and persistence you will find them. Typically at dealerships, yes, but here's a time where spending a few extra bucks at a dealership to pay for great experience and training is very much worth while. The 6.0L Diesel as an engine is very good, however some of the early electronics, software and issues related to maintenance during ownership are the main things that tarnish the image. The block and heads in and of themselves are excellent, designed and manufactured by Navistar (International Harvister). With the exception of some oil leaks, the base engine is a solid deal. I wish you luck in your repair quest - try what I suggested, and if it doesn't work, keep the faith and find some solid help and you will have luck.