Ive done 7k in my 12 burb 1500 with a 5.3 and 3.08 gears.. The xl burb platform does well trailering surprisingly.. The longer wheel base helps... Tongue weight is the key for keeping her stable... I would step up to 2500 if I had the option due to the 6.0 and little stiffer suspension. But the denalli is a good bang for the buck mid weight hitter. I really think the axle ratios are key to keeping things in line. 3.42 would be ok, 3.73 is better and normally in the 4wd models. My experience with 7k on my 2wd... I had a bit too much tongue weight, rear felt a smidge washy in corners, but took it slower and worked out fine. The Donzi has a lot of its weight on the axles and tongue weight is a lot more manageable. I am guessing the trailer has hydraulic brakes? Make sure they are in good working condition. The extra torque of the 6.2 or 6.0 is a beautiful thing towing, your main hurdles to work with are trans, and suspension and brakes.. Trans lock it in 4th gear with tow haul on... I agree with previous post of a tune to help quicken the shifts, it cuts down on trans heat a lot... Its not going to pull like the Duramax but for a suv it will tow better than 99% of the market right now. If your wanting to tow with it more often, I suggest a sway bar upgrade on front and rear. Helps plant the suspension. tires need to be aired up for the extra weight. Id put 40-44 in the rear tires that should be max pressure if I am right... I think you will find that its a very capable vehicle... Just don't expect to win any races towing but will do fine. The highway manners are good, a sway bar would help in sweeping corners where you can feel the load lightly push you. I was more confident in my burb with 7k on it than most of the stuff I have towed with, just needed more power down low, had to run the 5.3 to 3500 on the shifts to be in power band... I hope this helps bud.
