One problem related to diesel engine has been reported for the 2007 GMC C4500. The most recently reported issues are listed below.
Truck lost almost all power and barley moved itself from the travel lanes to the side of the road, had to be towed and after a week in the shop! at my business loss . A crank sensor was determined to be faulty,then an e. G. R valve and finally replaced the p. C. M. Check engine light still on and off and still weak on power. Fuel usage is horrible most of the time 6 -7 mpg. Truck currently towed to another dealer for a transmission problem, it wont move!! I found trans to be almost out of fluid. I check fluids regularly. Truck has 16k on it now. And this is the second tow, the first at 2,000 miles.