Understanding that your situation has changed and the point may be moot but here is my take. We had several 1/2 ton 5.3 equiopped GM vehicles that we towed our 6500# 27ft trailer with. First off, the gear ratio of 3.08:1 is not a limiting factor. If you are towing a travel trailer the profile and aerodynamics are what will slow you donw much more than the weight. NONE of my trucks would tow in overdrive no matter how flat or how little wind there was. The gas 5.3 simply does not have the torque to pull in OD without picking back and forth between 3rd and OD, this will kill a trans. I had an 4wd Avalanche with 4.11 gears that ran high RPM in 3rd, I had a 4wd ext cab pickup that had a 3.73 that was a little better and a 3.42 2wd suburban that was the best of the three since it had lower RPM and still was in the torque and power enough to pull the load. The avalanche was supposed to have a "tow pkg" but did not have an external trans cooler, I added an OEM setup that GM should have put on (this was a huge debate over why GM didnt put it on but mostly came down to them cheaping out) An add on extrenal trans cooler is not all that hard to put on a GM truck, E trailer dot com has them, if you are an average home mechanic you can do it yourself, just make sure you use "transmission" rated rubber hose on your connections or any trans shop can do it for you. You would then be able to tow without wiping out your trans and just keep the truck in 3rd gear. The other issue with the tahoe is the short wheelbase which limits the length of trailer that they can safely pull. Just becasue you can pull 7000# doesnt mean you can pull a 32 ft trailer, personally I think anything over 25 ft is foolish with even the best anti sway hitch setup. think of the "tail wagging the dog" if the trailer sways it exerts force on the tow vehicle, the short wheelbase is less capable of absorbing the side forces since it has less length for leverage against the force. Hopefully your situation will change and you can get your life back to camping. Good luck