Again, sorry for the confusion. The denali has the power it's just not made to tow. From what I understand now is the 6.2 is a performance engine and the 6.0 is a proven towing machine. Imo when you run a trans and engine at hotter temps for trips you are obviously pushing both too hard. This is the problem that I had with the denali. I was babying it the whole way and still it would heat up.
In comparison my dad just got rid of a 09' 2500 quad cab with 6.0 and 373 gears. He pulled a 5th wheel that weighed 9000+ all around the country with no issues whatsoever. Engine temp stayed the same always and tranny would run in the 170's most of the time. I'm pretty sure the 08' + 2500 burbs have the same frame and drive train as my dads. 6.0 + 6l90+ 373 or 410 rear end.
