I need to bring this thread back up to report that I found some information on the Duramax (GM) diesel warranty. The webpage is: http://www.duramaxdiesel.com/07_warranties/index.htm
It says, in part, "Duramax Diesel Engine Coverage
The engine is covered by a five year or 100,000 mile (whichever comes first) limited warranty. A deductible per repair visit may apply after the vehicle has been in use for 3 years or 36,000 miles, whichever comes first. See dealer for more information.
So there is a 100,000 mile warranty, but with a deductible after 3/36.