Here is my report, first, my Tahoe has the max towing package (3.42 gears, integrated trailer brake, rear air suspension, it is also a 4x4, rated at 8200lbs for towing. I have a 28 foot travel trailer that is 5700lbs dry. Since I am dry camping for 5 days, I need the water and propane topped off. I figured with wife and three kids worth of "stuff" we add about 1200lbs including water, propane and gear. That brings my trailer to 6900lbs, well within limits.
Setting up the hitch (tahoe has 20" wheels): I had to adjust the hitch to a lower setting (previous setting was for a 99 Suburban). The tahoe is 3 inches "taller" at the hitch than the OBS suburban. I was contemplating the weight distribution bars, do I need them or not, I figured with the air suspension I probably didn't, but in the back of my mind, why put the extra strain on my tahoe, so I did add the bars, I also installed the sway bar (remember you MUST have a sway bar in CA if the trailer weighs more than 3000lb pounds), and finally hooked up the electrical.
I then went to the local school parking lot to setup the brake controller, very easy to use.
Then off we went (forgot to mention Tahoe was topped off with premium gas, I always use premium for towing, 26 gallons). Acceleration was great merging onto the freeway (tow/haul mode is on). First grade was the Cajon Pass, not a very difficult grade 3-4% if that, 7MPG, I was in the lane next to the truckers lane, average 52-57MPH, not bad. Got onto the 395 north, 17 miles of 50MPH max for road construction (what a pain). After that 55-65MPH, 13-15MPG. Arrived in Bishop, topped of gas, had lunch, back on the road.
Second grade (IDK the name) is a few miles north of Bishop, much shorter than Cajon, but much steeper, 4-5%, averaged 4MPG, but only took 15 minutes.
Now in the high country, with the third and final grade, again steep and short, I would guess same percent as second grade, 4MPG also.
We arrived at our campsite at 4pm in the afternoon, leaving at 7am in the morning. Not 1 issue with the Tahoe, trans temp did not get hotter than 205, engine oil temp did not seem to rise much. I set the cruise to 60 MPH, 80% of the time, with tow/haul on the duration of the drive. Granted we did drive through the desert in the morning, I would guess 3-5 degrees hotter for the fluids if driving during peak temps.
Disclaimer, we drove from elevation of 1200 feet, to June Lake at 6700, not a whole lot of braking, but when I needed to brake you really couldn't tell the trailer way their. It took my wife and I about 15 minutes to setup the brake controller, read the manual!
Interesting items I noticed, only 1 time did the electric fans got to "max" speed, pulling out of Bishop (98 degrees) to start the 2nd grade, they stayed on the whole grade, as soon as we "leveled" off, they decreased speed. Going from a 4 speed with 3.73 (OBS Suburban) to a 6 speed with 3.42, I felt the Tahoe "pulled" better, the horsepower is probably a significant factor, 100 more HP than the vortec 350.
Just my $.02 on towing with the 15's.
