2026 GMC Terrain AT4 Fails to Make the Grade

GMC Terrain Joins the AT4 Lineup

The GMC Terrain has been on the market since 2010, offering buyers a compact crossover alternative to the brand’s better-known full-size SUV and pickup trucks. I’ve always liked the Terrain because it’s a small SUV with ample interior space, thanks to a wide stance that makes it look like a bulldog in more ways than one.

GMC expanded the Terrain’s lineup for 2026 by introducing two new variants, a luxury-clad Denali and an off-road-focused AT4. The ladder is what I’ll be discussing. I had plenty of time to learn if the new-generation Terrain had the chops to be an off-roader or merely wears the AT4 badge symbolically.

To my surprise, the Terrain failed to meet professional-grade standards as an off-roader. It served as a prime example of an ongoing issue in the compact SUV market regarding fuel economy.

GMC Terrain AT4 Features

The new 2026 GMC Terrain is the third-generation model, debuting in 2025, with a redesigned exterior and interior.

The Terrain has never been a beauty queen, but this latest evolution makes a gallant effort with rugged styling that presents an adventure-seeking profile with fenders and wheel arches that bulge out like a lumberjack’s forearms. Its signature wide body and narrow roofline project a broad-shouldered, muscular appearance.  

The GMC AT4 trim level encourages buyers to select two-tone colors, such as the model shown in the photos wearing Riverstone metallic ($495) with a Twilight roof ($495). AT4-branded Terrains come equipped with red tow hooks at the front and capable-looking all-terrain tires wrapped around a set of 17-inch machined aluminum wheels to support the increased ground clearance and standard all-wheel drive.

Interior Highlights and Features

The interior, although spacious, lacks style. The only eye-catching aspect of the cabin is the massive 15-inch diagonal center screen which projects a geographical-inspired greeting display when you enter the vehicle. It certainly looks cool, but I would argue that having a large screen do all the heavy lifting of a car’s interior design is lazy.

I will give credit to GMC for including analog buttons at the bottom of the screen as a secondary option for managing audio volume and climate controls. The only problem is that these analog toggle switches can be pressed unintentionally when dropping items directly into the tray in front of them.

The headlight controls can only be accessed via the touchscreen. General Motors has been doing this for years and still annoys me when I look around the dashboard for a physical switch and remember I have to look for the light bulb icon on the center screen.

Big Space in a Small SUV

On the bright side, the Terrain AT4 cloth seats offer excellent support with a forgiving softness in the material. The optional all-weather floor mat kit ($350) ensures spills, and anything stuck under your shoe stays on the mat and off the carpet. The rear cargo space is great for the compact classification, rivaling the amount of space found in a mid-size SUV.

The wheel well humps will prevent you from sliding a sheet of plywood but overall has plenty of room to transport supplies for a weekend expedition. I used it as a mobile garage carrying tools, a hydraulic jack, impact drill, jumper cables and an air compressor to bring my newly acquired 1971 Ford Thunderbird back to life after a 15-year slumber.

Not Enough Power for a Professional Grade

The real disappointments lay under the hood. The Terrain features a 1.5L turbocharged four-cylinder engine making 175 horsepower and 203 pound-feet of torque. Entry-level models, like the Terrain Elevation, with front-wheel drive feature a CVT transmission, while the AT4 and other variants with all-wheel drive utilize an eight-speed automatic transmission.

For city commuting, this engine is adequate if not mundane. The Terrain’s driving personality will not leave a lasting impression. It does its job as a personal means of transportation and nothing less, but nothing more either. It felt fine until I ventured onto the open highway, using cruise control and lane assist, and was shocked to see the average MPG.

Lackluster Fuel Economy

Driving the GMC Terrain AT4 for over 380 miles, I averaged 22 mpg overall. I don’t understand how a so-called compact SUV with a tech-savvy turbocharger, monitored by an engine management system that could power the Apollo lunar space missions, can fail to average 25 mpg in the futuristic present of 2025.

The trip computer indicated that it had previously achieved a “best” average of 28 mpg. I couldn’t imagine how that was accomplished, short of driving as if you were transporting nitroglycerin. Its saving grace is the modest-sized 14.8-gallon fuel tank, which doesn’t require much to fill up.

Off-Road for Show

This SUV has the ground clearance, tires, drive modes, and all-wheel drive to suggest it can handle a bit of abuse on the road less traveled. As part of the road test, I took the Terrain AT4 out to the ranch to find out if I could cash the check it wrote.

The test was within reason, nothing crazy, consisting of 45 minutes traversing dirt hills and uneven trenches near a pond. The kind of terrain you’d expect on a camping trip far from the paved parking lot of a National Park’s visitor center.

The GMC Terrain AT4 handled the rugged trails better than expected. It did not hesitate, nor did it feel like I needed to strain its mechanical components to tackle obstacles.

Everything was fine until I got back on the highway and noticed the SUV pulling sharply to the left if I let go of the steering wheel. A mild stroll at a ranch was enough to throw off the SUV’s wheel alignment. I’ve taken several test vehicles through the same off-road routine with no lasting effects. It caused me to lose confidence in the SUV’s proclaimed all-terrain capability.

What good is a sports utility vehicle if it loses its composure after 40 minutes of playing in the dirt?

An SUV that Works Best with Less

The entry-level Terrain Elevation (with front-wheel drive) starts at a rounded-up $31,300, offering its best attribute of interior space without the overly ambitious promises of luxury or off-road prowess that the AT4 and Denali can fail to achieve.

The GMC Terrain AT4 shown in this review is priced over $43,000. While not overly expensive, I don’t think you need to spend that much to enjoy the benefits of this particular SUV.

Engine: 1.5L Turbocharged four-cylinder

Transmission: 8-speed automatic

0 to 60: 7.9 seconds

Starting Price: $31,295 (Elevation FWD)

Price as Shown: $43,380 (AT4 AWD)