I have been fretting about the shortage of qualified diesel mechanics in the San Antonio area to service my soon to be ordered D/A. Some local dealers are without trained diesel mechanics and some dealerships have mechanics with some training but not a lot. I have yet to find a dealership that has a diesel mechanic with extensive training on diesels. I am however still looking. I happened upon a commercial selection in the GMC site that listed 2 GMC commercial heavy duty dealers in my area, I called them up and spoke to the service department and to my relief they both said yes that they can and will work on the Duramax engine.....this is after the warrenty expires as they will not do warrenty work. They explained to me that their diesel mechanics are highly trained, certified and experienced, and in fact it takes them less time to troubleshoot and repair the Duramax than the regular dealerships do that sell trucks. One of them also does work on Allison transmissions but the other does not. So my quest is over and when my truck is out of warrenty I know where to take it. to be fair, some dealerships in other areas of the country do have properly trained mechanics but so far I haven't found any here except at the mentioned commercial dealers.