Used 2020 GMC Sierra 3500HD for Sale nearPhoenix, AZ

How much does the 2020 GMC Sierra 3500HD cost?

Prices have softened 7.74% compared to this time last year, making it a favorable time to shop this model year.

There are 510 listings available, which gives you a meaningful amount of inventory to compare.

Is the 2020 GMC Sierra 3500HD a good car?

Yes — the 2020 GMC Sierra 3500HD earns a 5/5 user rating, which points to strong owner satisfaction. Owners repeatedly praise its impressive performance when pulling heavy loads, its comfortable and well-built feel, and its strong track record compared with competitors. The overview also shows why it fits your needs if you want a serious tow rig that still feels modern and well-equipped, especially with its broad range of cab, bed, and rear-axle configurations. With 34.5% of listings marked as good or great deals, you have some room to shop selectively.

Is the 2020 GMC Sierra 3500HD reliable?

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

The owner feedback points to a truck that feels dependable and well-built, with many shoppers trusting it for heavy-duty work and long-term use. That kind of confidence matters most if you plan to keep the truck for towing, hauling, or regular jobsite duty. For used buyers, the main long-term ownership risk is less about the rating and more about making sure the specific truck you choose has been maintained properly and hasn’t been worked harder than its condition suggests.

What should I look for when buying a used 2020 GMC Sierra 3500HD?

Accident-free inventory is solid at 77.6% — always verify the vehicle history report.

You should start with the history report so you can confirm accident status, title history, and any signs of heavy-duty use that may not be obvious at first glance. Then prioritize a thorough inspection of the truck’s condition, especially if it was used for towing or hauling, because that kind of work can accelerate wear. Focus on the overall state of the drivetrain, suspension, brakes, and interior, since a clean-looking truck can still hide hard use.

Is now a good time to buy a used 2020 GMC Sierra 3500HD?

This is a moderate market, so you can shop selectively without expecting a deep buyer’s market.

• Deal availability: 34.5% of listings are priced as good or great deals.
• Inventory: There are 510 listings available.
• Price trend: Prices have softened 7.74% compared with last year.
• Clean inventory: 77.6% of listings are accident-free.

If you find a listing below $49,979, that's toward the low end of the year-round range and worth acting on quickly.

What is the 2020 GMC Sierra 3500HD's resale value?

The current average of $49,984 sits slightly below last year's $54,177.

That decline suggests the market has become a bit more favorable for buyers, but it also means future sellers may need to price carefully to stay competitive. If you buy well now, you may have a better chance of limiting depreciation pressure later, especially if you choose a clean, well-kept truck with strong equipment and a desirable configuration. Trucks that are priced right and present well tend to move more easily when it’s time to sell.

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

Should I buy a 2020 GMC Sierra 3500HD 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:

• 34.5% of listings are priced as good or great deals.
• Accident-free inventory is solid at 77.6% — always verify the vehicle history report.
• Price trend: Prices have softened 7.74% compared with last year.
• Owners rate it 5/5 — a strong satisfaction signal.

The bottom line: If you want the redesigned 2020 model year with strong owner satisfaction and a softer price than last year, it’s the primary year to target. If you’re especially price-sensitive, you can also compare nearby years to see whether a lower entry price outweighs the 2020’s stronger market position and updated design.

These recommendations are based on CarGurus' proprietary market data from October 6, 2026, CarGurus experts' opinions, and generative AI.