Its pretty sad when you learned more than the dealer about duramax's by reading bs online. I still call them and ask questions for a good laugh, the result of there answer is come on in and we will spend your money. I live in a small town have started doing diesel repairs after ppl get sick of spending money and no fix they find me, and I learned fixing my own because the freakin dealer couldn't give me a straight answer.
Same goes for gasers. there is more to it these days than having a certified piece of paper
No offense meant to you by this statement but I work at a dealer and if someone calls in wanting free info on how to fix their trucks I won't give it out either. My boss didn't spend this kinda money on shop equipment for free info. Just saying