Used 2020 GMC Sierra 2500HD for Sale nearStamford, CT

How much does the 2020 GMC Sierra 2500HD cost?

Prices have softened 4.79% compared to this time last year, making it a favorable time to shop this model year.

There are 1,145 listings available, which gives you a solid pool to compare trims and condition levels. If you find a listing below $48,764.78, that's toward the low end of the year-round range and worth acting on quickly.

Is the 2020 GMC Sierra 2500HD a good car?

Yes — the 2020 GMC Sierra 2500HD earns a 4.86/5 user rating and an 8.17/10 expert rating. The standout strength is Form and function at 10/10.

Owners consistently praise its performance, comfort, and towing capabilities, and they also highlight its power and appealing features. The truck’s use-case appeal is clear if you want serious heavy-duty capability with a more premium-leaning identity and plenty of utility. The main trade-offs are that it is expensive for the class and its cabin materials and fit and finish do not fully match the luxury billing. Even so, 29.3% of listings are priced as good or great deals, so you still have room to shop selectively.

Is the 2020 GMC Sierra 2500HD reliable?

Owners rate it 4.86/5, a strong signal of long-term satisfaction.

The owner feedback points to a truck that feels dependable in daily use, with praise centered on performance, comfort, towing capability, and power. The expert drive notes also reinforce that it is built around serious work-truck durability and heavy-duty capability, with the diesel powertrain described as delivering massive, sustained grunt. GMC also includes helpful trailering tools and camera support that make ownership easier when you are using the truck for demanding jobs.

For used buyers, the main long-term ownership risk is less about the truck’s core capability and more about paying close attention to condition, maintenance history, and how hard the truck was worked.

What should I look for when buying a used 2020 GMC Sierra 2500HD?

At 73% accident-free, a meaningful share of listings has prior incidents — history verification is especially important.

You should start with a vehicle history report and then prioritize a thorough inspection of the body, frame, cabin, and towing-related equipment. Because this is a heavy-duty truck that may have been used for demanding work, condition matters as much as mileage. Focus especially on signs of wear that could point to hard use, and make sure the truck’s features and equipment all operate as expected.

Key things to evaluate:

• Trim level: The base truck comes standard with a V8 engine and a 7-inch touchscreen with Apple CarPlay and Android Auto, but frills are minimal. The SLE adds 17-inch aluminum wheels, two-tier trailering mirrors, an EZ lift-and-lower tailgate, a 4.2-inch driver-information screen, a 4G LTE WiFi hotspot, cruise control, carpeted floor covering, remote keyless entry, and a leather-wrapped steering wheel. The SLT adds 18-inch aluminum wheels with black accents, LED bed lighting, LED fog lights, chrome door handles and mirror caps, a power-release tailgate, the Multi-Pro six-way tailgate, 10-way power-adjustable front seats, wall-style power outlets, and an 8-inch infotainment touchscreen. The Denali adds a full leather interior with wood-grain inserts, navigation, wireless device charging, and a Bose premium sound system.
• Powertrain: The truck offers two 6.6-liter V8 engines, one gas and one diesel. The gas V8 makes 401 horsepower and 464 pound-feet of torque, while the Duramax diesel V8 makes 445 hp and 910 lb-ft. The gas engine uses a 6-speed automatic, and the diesel uses a 10-speed Allison transmission. The diesel delivers especially strong low-speed and highway pull, while the truck’s size means a poor turning radius and plenty of planning in tight spaces.
• Safety package: Standard safety features include front- and side-impact airbags, traction control, a reversing camera, and a tire pressure monitoring system. The Driver Alert Package I adds front and rear parking sensors, blind-spot monitoring, and rear cross-traffic alert. The Driver Alert Package II adds forward-collision avoidance, lane-departure warning, and automatic high beams.
• Infotainment: The standard setup is a 7-inch touchscreen running GMC Infotainment 3 with customizable icons, Apple CarPlay, and Android Auto through USB. The SLT and Denali upgrade to an 8-inch screen, and both are available with navigation. The Denali also adds an 8-inch color driver-information screen.
• Fuel efficiency: In mixed driving, the truck returned 16.5 miles per gallon.

Which 2020 GMC Sierra 2500HD trim should I buy?

The 2020 GMC Sierra 2500HD is offered in 4 trim levels: Sierra, SLE, SLT, Denali.

Here's the short version:

• Sierra: This is the entry point, and it gives you the core heavy-duty hardware plus a V8 engine and a 7-inch touchscreen with Apple CarPlay and Android Auto. It makes sense if you want the lowest starting point, but the content is sparse enough that many shoppers will want to move up.
• SLE: This is the best-value trim for many buyers because it adds useful everyday upgrades like trailering mirrors, remote keyless entry, cruise control, a WiFi hotspot, a better driver-information screen, and a leather-wrapped steering wheel without jumping into luxury pricing.
• SLT: This is the sweet spot if you want a more upscale truck without going all the way to Denali pricing. You get the 8-inch touchscreen, power-adjustable front seats, wall-style power outlets, LED bed lighting, LED fog lights, and the Multi-Pro six-way tailgate.
• Denali: This is the luxury-leaning choice, with full leather, wood-grain trim, navigation, wireless charging, and a Bose premium audio system. It suits you best if you want the most premium cabin and are willing to pay for it.

The safety package is split across the Driver Alert Package I and Driver Alert Package II, so check carefully for those features if they matter to you.

Is now a good time to buy a used 2020 GMC Sierra 2500HD?

This is a moderate, selective buyer’s market, so you can shop with some leverage if you are patient and focused.

• Deal availability: 29.3% of listings are priced as good or great deals.
• Inventory: There are 1,145 listings available.
• Price trend: Prices have softened 4.79% compared with last year.
• Clean inventory: 73.0% of listings are accident-free.

If you find a listing below $48,764.78, that's toward the low end of the year-round range and worth acting on quickly.

What is the 2020 GMC Sierra 2500HD's resale value?

The current average of $49,184 sits slightly below last year's $51,658.

That softer pricing suggests the market has already adjusted downward, which can help you buy at a more favorable point in the cycle. For a future seller, that also means your resale outcome will depend heavily on condition, mileage, and how well the truck has been maintained. Heavy-duty trucks can hold buyer interest when they are clean and well cared for, but the premium pricing of higher trims means depreciation can still be meaningful.

Vehicles with strong owner satisfaction ratings, like this model year's 4.86/5, tend to retain buyer demand, which supports resale value over time.

Is the 2020 GMC Sierra 2500HD safe?

It earns an 8/10 safety score from our experts.

The truck’s size creates real maneuvering challenges, but GMC helps offset that with cameras on all four sides and two-tier trailering mirrors. Standard safety equipment includes front- and side-impact airbags, traction control, a reversing camera, and a tire pressure monitoring system. Driver Alert Package I adds front and rear parking sensors, blind-spot monitoring, and rear cross-traffic alert, while Driver Alert Package II adds forward-collision avoidance, lane-departure warning, and automatic high beams.

Because this truck is so large, you should pay close attention to visibility aids and parking-assist features when shopping used examples.

Should I buy a 2020 GMC Sierra 2500HD or consider a different year?

If you're weighing the 2020 against nearby model years, here's how to think about it:

Choose the 2020 if:

• 29.3% of listings are priced as good or great deals.
• At 73% accident-free, a meaningful share of listings has prior incidents — history verification is especially important.
• Price trend: Prices have softened 4.79% compared with last year.
• Owners rate it 4.86/5 — a strong satisfaction signal.
• The 2020 model year combines heavy-duty capability with a luxury-leaning Denali identity and strong towing-focused utility.

The bottom line: If you want a heavy-duty truck with strong capability, premium-leaning features, and a market that has softened enough to create some buying opportunity, the 2020 is a solid path. If you are especially price-sensitive, you may want to compare it carefully against nearby years and focus on the cleanest, best-maintained truck you can find rather than chasing the newest badge.

These recommendations are based on CarGurus' proprietary market data from September 4, 2026, CarGurus experts' opinions, and generative AI.