Overall, I am very pleased with my Duramax CCSB Z71 4WD. However, it is narrow for a 7' wide trailer. I wish GM would make the black plastic snap-on mirror extensions for the small truck like they do for the big Silverado. These "mirror snaps" cover the entire front of the mirror and add a mirror on the outside in the rear. They look good, unlike the rubber-strap temporary mirror add-ons that I have. What I have works, so I put up with UGLY, but better would be appreciated. These mirrors do NOT need to be $500 either! I don't know of any wider mirrors for the Colorado - anyone know different?
I just came back from towing my Cargo-Trailer-ToyHauler-Camper (weight 4760# loaded (820# motorcycle), 7'Wx14'Lx6'H) on 1000 mile trip to Canyonlands Park,near Moab Utah. It was my first row-haul trip. I had the combination weighed (for free) at a Utah truck weigh station. Total was 10080#. The truck itself was 5320# with full tank, spare tire, cooler, tools, misc stuff in the back and me in it (195#).
I was pleasantly surprised that mpgs were 15.7 going down fro near Yellowstone Park. The way back was a Very fierce headwind, terrible! It was 35-45 mph headwind and bigger gusts. Still, mpgs were not that bad at 13.5 and 65 mph still OK.
My Toyota 4 Runner would only get 12 mpg pulling 1400# open flatbed with motorcycle on it. Hills and mountains were a total pain, 3rd gear, maybe 40-45 mph up the slope working like mad. I doubt the 4Runner would pull my ToyHauler-Camper up the mountains. The Duramax, same hills with the bigger loaded trailer, 65 mph no problem no sweat. Most of the time, rpms were in the 1500-2000 range.
I was in trailer park near Canyonlands and 2 spaces over was a fellow with a big size Duramax. Of course he wanted to ask about my "baby Duramx", I told him my mpgs and performance; he couldn't believe it. He said he gets 8 or 9 mpg in his big Duramax, and very few times in the 10s. I let him turn on my Colorado because I leave the Trip A/mpg screen on all the time. He turned it on and there was the number 15.7! He was amazed. He is now (maybe?) considering getting a Colorado because it does a better job than his 3 year old Big Duramax. He said he didn't even know about this Colorado Duramax truck - very little if almost no advertising by Chev/GMC. I see TV ads, but have not seen one that featured or talked about a Colorado/Canyon. A passing photo op in the middle of other trucks is the most I have seen.
It is a pain to add DEF, there should be some easier way to keep it from spilling over on side of truck. Diesel is OK, I add the cold weather treatment (6.5oz/20 gallons) in the winter. I have only done that 2 times so far. I have 4200 miles on truck now in 8 months ownership. This truck regularly gets 25-27 mpg in town, sometimes drops to 23-24. On highway w/o trailer I get 28-29, and a few trips at 30-31 mpgs. I bought this truck with heavy bargaining/dealing because the 2019s were sitting right next to it and dropped the price by sizable amount, no matter what the Blue -Books/etc said. I have never seen a Blue-Book" buy anything!
This is my new-or-any first american vehicle of any kind in over 26 years. The Colorado is my first Chevrolet. I wouldn't buy any of them (american or foreign) or Toyota Tundra/Tacoma, etc because of crappy gas mileage. A used 2000 Subaru Outback was pretty good at 25-30 mpgs, that is, until it threw a rod (or something) and seized at 147K miles at the bottom of my driveway, value $5000 to ZERO$ in an instant. I never mistreated it or raced around, nice little car, comfortable, and big enough. I still have the 1996 4Runner, only 168K miles, no problems, still runs like it always does, is reliable.
Just my observations and opinions.