It’s always a good thing when we get to this point in the lifecycle of a long-term test vehicle and have nothing of any grave importance to report. Such is the case with our 2021 Four Wheeler of the Year award-winning 2021 GMC Yukon AT4. After 9 months on the road and more than 16,000 miles the Yukon is still rock solid, and we are just as enamored with the vehicle today as we were on the day it was dropped off.
During the first half of the year, we spent a fair bit of time with a trailer in tow. With 355 hp and 383 lb-ft of torque on tap from the 5.3-liter V-8 engine, and a respectable tow rating of 8,200 pounds, the Yukon AT4 has proven itself to be a competent tow rig. The one area that we’re not as certain about is the adjustable air suspension while towing. The system has a number of positive attributes, with the most useful being automatic load-leveling and the ability to raise and lower the vehicle’s height while hitching. On the flip side, there are several small quibbles that we’ve bumped up against that we feel need addressing.
Previous reports: Report 1 (Feb. 2022) / Report 2 (May 2022)
The same automatic load-leveling ability that we enjoy on the road has made unhitching difficult on many occasions, especially when the trailer isn’t level with the vehicle, because it will continue to adjust even when the vehicle is off. We also have the setting activated that automatically lowers the vehicle down to the lowest entry level when placed in Park. This is great, except when attempting to hitch a trailer. We wish there was an easy way to lock out the air suspension when towing, as it would be quite helpful to have full control over the suspension without the vehicle doing anything automatically. Additionally, we got a strange error message while towing a side-by-side on our utility trailer. The full load was about 5,000 pounds with approximately 500 pounds of tongue weight, well within the Yukon’s limits. Upon arriving at the desert and unhitching the trailer, the vehicle flashed “Height adjustment unavailable, air suspension overloaded.” It took several miles of driving and key cycles to get this to clear and allow us to bump into the higher off-road suspension settings. We hadn’t seen this prior, and haven’t since, so we’ll be watching for it in the final quarter.
Speaking of the 2021 GMC Yukon AT4’s air suspension, we ran some incredible off-road trails this quarter and had a chance to use all of the vehicle’s off-road hardware. With the Yukon’s transfercase shifted into low-range we were able to raise it into the highest suspension setting, which provides an impressive 34.5-degree approach angle, 22-degree breakover angle, and 10 inches of ground clearance. We waded through two feet of water, drove through soft sand, climbed steep hills, traversed rock-strewn riverbeds, and blasted down graded roads. About the only thing we didn’t do was hardcore rock crawling … for obvious reasons.
We still appreciate the Yukon AT4’s electronic rear limited-slip differential, which works quite well when traction starts to decline. Selecting the “off-road” drive mode (the Yukon AT4 features Normal, Tow/Haul, Off-Road, and Sport drive modes) improves throttle mapping and transmission shifting when in the rough. And the Yukon AT4’s standard hill descent control is certainly useful for those who choose to use it. Like most air-suspension-equipped off-roaders, we’ve found the Yukon AT4’s ride quality degrades significantly the higher it is raised (it’s still better than most, however, thanks to the active ride control dampers). While the extra 2 inches of ground clearance is nice when going over large obstacles, we’ve found that the normal ride height is the most comfortable for most general off-road scenarios. Unfortunately, it looks like we’re going to go another year with no opportunity for snow or mud wheeling on the West Coast. While we’re confident in the Yukon’s snow ability, we’d try our hardest to avoid deep mud holes, but that’s more a personal preference anyway.
What’s Hot, What’s Not
- Hot: Gorgeous styling continues to attract attention, 5.3-liter V-8 engine is plenty powerful, all seven seats are comfortable for full-grown adults
- Not: Panoramic sunroof is good for watching the carwash brushes and not much more, fuel economy is still on the lower end, wireless Apple CarPlay has gotten a tad buggy
Moving back inside, the interior continues to prove to be a comfortable fortress of solitude most of the time. If we were going to spec out the Yukon AT4 again, we can say at this point we’d find a way to not have the panoramic sunroof. Personal preference plays a large role in this; however, we’ve found that the glass roof and cloth cover do let in quite a bit of heat and noise. Unfortunately, the sunroof is grouped together with the AT4 Premium Plus Package, so it would take some clever optioning to get the features we love without the glass roof. Another polarizing feature that we love is the head-up display. We leave it on speed most of the time, but it has the ability to display off-road data, stereo information, and navigation. It’s become such a useful tool that we don’t know how we’ll live without it when the Yukon is gone.
We’ve stuffed adults in all three rows of the GMC Yukon AT4 and have not had a single complaint. The middle row captain’s chairs both recline and slide, while the third row now has much improved leg room thanks to the Yukon’s new independent rear suspension. There are even USB-C charging provisions for all except the rear center passenger, which is pretty impressive.
As we enter the final quarter of evaluation, we’re displeased by the proposition of returning the 2021 GMC Yukon AT4 to its rightful owners. Having just completed the second scheduled service at 15,000 miles, we don’t foresee another dealer visit. So, all that is left for us to do is enjoy our remaining months with the large SUV. Sticking with the plan that’s worked so far, we have more off-roading, towing, and road trips on the books. Here’s hoping for another trouble-free quarter as we send the Yukon AT4 off in style.
Price: 2021 GMC Yukon AT4
Base price: $64,800
Price as tested: $75,605
Long-Term Numbers
Miles to date: 16,241
Miles since last report: 4,718
Average mpg (this report): 13.58
Test best tank (mpg): 18.78
Test worst tank (mpg): 9.28 (towing 8,000 pounds)
Maintenance
This period: oil change, tire rotation, air filter, fluid top-off (15,000 miles), backup camera recall
Problem areas: None
Logbook Quotes
- “I’m really glad the Yukon has a small gas tank now, as it takes two card swipes if I let it go below a quarter-tank … yikes. “
- “We have FINALLY found a good use for the sliding center console! It perfectly holds the giant tub of cheese puffs for road trip snacking!”
- “The compliments keep pouring in for the Yukon AT4, from the old man at the gas pump to the parents at Disneyland and everywhere in between. “
- “Just went through a deep water crossing in our factory AT4 while laughing at all the kitted out Jeeps that followed. “
Options As Tested
- AT4 Premium Package ($9,145)
- Cayenne Red Tintcoat paint ($645)
- Second Row Heated Bucket Seats ($370)
- Power Sliding Center Console ($350)
More Details: 2021 GMC Yukon AT4
Backcountry exploration is really what the GMC Yukon AT4 is best suited for. Getting out and finding abandoned mines and old relics from centuries past is one of our favorite pastimes, and the Yukon AT4 is one of the most comfortable and capable SUVs for the activity.
We would still love it if GMC could find a way to package the fantastic 3.0-liter Duramax diesel I-6 engine from the Yukon Denali in the AT4. Allegedly, the AT4’s front skidplate interferes with the diesel engine’s charge air cooler. Still, the prospect of 460 lb-ft of torque with 26 mpg on the highway is quite enticing.
The combination of our Yukon AT4’s Cayenne Red paint, dark chrome trim, front skidplate, and off-road tires gives the vehicle quite the sinister look. And it has attracted attention everywhere we go. People simply love the Yukon AT4.
This little cubby here, at the front of the center console, contains the SUV’s wireless phone-charging pad. Simply drop your device on the pad and it will automatically begin charging. Trouble is, our standard-size iPhone isn’t large enough to stay centered and would frequently drop the charge just by slipping to one side or another. Needless to say, this spot now just collects junk.
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Keyword: 2021 GMC Yukon AT4 Long-Term Report: a Lot of Off-Roading, a Touch of Towing, and More Fun Features