I have just picked up my 2012 F-350 with the 6.7 litre diesel from the dealer for the second time in about 3 weeks.  What's the problem?  I'm glad you asked.

These trucks have 4 EGT sensors on the exhaust system that are failing between 50,000 and 70,000 miles.  When they fail and they do without any warning whatsoever, you are dead in the water.  The truck will start to shift down until you reach a creep speed and then shut off.  You can't start it again without the Ford dealer overriding the system and clearing a code.  Even so it will immediately happen again and again until the affected sensor is replaced.  An aftermarket code reader will not clear the fault code.  It was described to me by the mechanic yesterday as a hard code that only a Ford tech can clear.  The sensors are about $60 apiece and the labor is about $300. 

If you have 50,000+  miles on your truck, I highly reccommend that you make a beeline to the nearest Ford dealer and get it done.  You will have to pay for it as the warranty doesn't cover the repair, but you will avoid getting left high and dry at a most unexpected location.  You will save a tow bill too.

About three weeks ago at 10:30 pm my daughter was shut down on I-35 in Oklahoma while pulling a loaded trailer.  She had to wait until we could get it towed off the highway.  I'm just glad her cell phone had a connection so she could call for help.  One sensor was replaced and the truck sent out the door.

Yesterday I was driving and pulled up to the fuel pump.  Filled the truck, got in, started it up normally without any codes or warnings and put it in drive.  The truck took off and immediately shut down.  I had moved forward about 10 feet.  Once again I had to call and have it towed to the nearest dealer.  This time I told them to replace the remaining 3 sensors that hadn't been replaced.  The service manager told me that they were seeing these trucks come in with a bad sensor between 50,000 - 70,000 miles.  He has some customers that are now carrying extra sensors with them.  I'm thinking it would be pretty hard to replace them on the side of the road somewhere, but I guess at least a Ford mechanic could be called and save a tow bill if you had an extra sensor with you.

Ford is likely to get a lawsuit over this once someone looses their life because of this failure and forced shutdown.  It is very dangerous and cannot be overridden to "limp in".    I like the truck and the engine, but I sure don't like the forced shutdown when a sensor fails without warning.

Remember, you have now been warned.  I hope you take notice and don't get caught like myself and so many others.