LIKE2BUILD wrote:
The 6-speed, 6.0L GM trucks might be a completely different towing experience than the 4L80E.
KJ
I think you might be surprised at the newer 6.0. My father in law tows about 9000 lbs with his 2011 Chevy 6.0 with no problems at all. towing mileage obviously isn't as good as my Cummins, but it handles the weights just fine. You can probably find a used 6.0 with lower miles for a lower price in better shape than a diesel. We are eastern US and traverse the mountain ranges in this area quite often. He has no problem generating enough power to tow at 65-70 mph.
Good luck!