GMC Sierra HD (2500HD/3500HD) trim levels explained
By CarWhere Research · Updated
The 2026 GMC Sierra HD comes in seven trims: Pro, SLE, SLT, AT4, AT4X, Denali and Denali Ultimate, with AT4X and Denali Ultimate added for 2024. GMC rates the 2500 HD at up to 20,000 lb conventional with the Duramax, and the 3500 HD dually at up to 36,000 lb with a gooseneck.
Current Sierra HD (2500HD/3500HD) trim levels: Fifth generation (2020–present)
Redesigned for 2020 with a 6.6L gas V8 and 6.6L Duramax diesel; the 2024 refresh added AT4X (2500 HD only) and Denali Ultimate and raised the Duramax to 470 hp and 975 lb-ft. For 2027 GM adds an available Duramax 8.3L V8 (555 hp/1,230 lb-ft) and up to 38,000 lb of gooseneck towing; 2027 pricing had not been announced. MSRPs below are 2026 2500 HD base prices.[1][2][3][4]
| Trim | Base MSRP (2026, USD) | Engines | Key standard equipment |
|---|---|---|---|
| Pro | $47,3002WD Regular Cab, excl. $2,495 destination; 2500 HD |
|
|
| SLE | $54,3004WD Regular Cab, excl. $2,495 destination; 2500 HD |
|
|
| SLT | $65,5004WD Crew Cab, excl. $2,495 destination; 2500 HD |
|
|
| AT4 | $72,5004WD Crew Cab, excl. $2,495 destination; 2500 HD |
|
|
| AT4X | $85,5004WD Crew Cab, excl. $2,495 destination; 2500 HD |
|
|
| Denali | $75,2004WD Crew Cab, excl. $2,495 destination; 2500 HD |
|
|
| Denali Ultimate | $94,2004WD Crew Cab, excl. $2,495 destination; 2500 HD |
|
|
MSRP excludes destination unless noted. "—" means we could not confirm the price from a GM or press pricing source.
Sierra HD (2500HD/3500HD) package and RPO codes (2020–present)
GM identifies packages and options with three-character Regular Production Option (RPO) codes, printed on the glovebox Service Parts Identification label and on the window sticker. The codes below are as listed in GM order guides and press material.
| RPO code | Trim | What it is | Source |
|---|---|---|---|
| 1SA | Pro | Pro preferred equipment group (2500 HD/3500 HD) | [1] |
| 3SA | SLE | SLE preferred equipment group (2500 HD/3500 HD) | [1] |
| 4SA | SLT | SLT preferred equipment group (2500 HD/3500 HD) | [1] |
| 4SB | AT4 | AT4 preferred equipment group (2500 HD/3500 HD SRW) | [1] |
| 4SG | AT4X | AT4X preferred equipment group (2500 HD) | [1] |
| 5SA | Denali | Denali preferred equipment group (2500 HD/3500 HD) | [1] |
| 5SB | Denali Ultimate | Denali Ultimate preferred equipment group (2500 HD/3500 HD) | [1] |
Previous Sierra HD (2500HD/3500HD) trim levels: Fourth generation (2015–2019)
The 2015–2019 Sierra HD used the 6.0L Vortec gas V8 and the 6.6L Duramax (LML through 2016, L5P from 2017). GMC offered an All Terrain package and, from 2017, an All Terrain X on 2500 HD Crew Cab 4WD. Launch MSRPs are not listed because we could not source them from GM.[6][7]
| Trim | Base MSRP (USD) | Engines | Key standard equipment |
|---|---|---|---|
| Sierra (base) | — |
|
|
| SLE | — |
|
|
| SLT | — |
|
|
| Denali | — |
|
|
MSRP excludes destination unless noted. "—" means we could not confirm the price from a GM or press pricing source.
2026 Sierra HD (2500HD/3500HD) towing capacity by configuration
Maximum ratings from GMC's 2026 Sierra 2500 HD and 3500 HD trailering charts. The top diesel figures require the Max Trailering Package, and some AT4, AT4X, Denali and Denali Ultimate configurations carry lower trim-specific ratings.
| Configuration | Max towing (lb) | Notes |
|---|---|---|
| 2500 HD 6.6L gas V8 – conventional, 18/20-in. wheels | 16,000[5] | 14,500 lb on 17-in. wheels |
| 2500 HD 6.6L gas V8 – 5th-wheel/gooseneck, Regular Cab Long Bed 2WD | 18,700[5] | |
| 2500 HD 6.6L Duramax – conventional | 20,000[5] | Max Trailering Package |
| 2500 HD 6.6L Duramax – 5th-wheel/gooseneck, Regular Cab Long Bed 2WD | 22,390[5] | Max Trailering Package |
| 2500 HD AT4X AEV Edition 6.6L Duramax – conventional | 18,400[5] | |
| 3500 HD 6.6L gas V8 – conventional, Regular Cab 2WD DRW | 18,700[8] | |
| 3500 HD 6.6L gas V8 – 5th-wheel/gooseneck, Regular Cab 2WD | 19,080[8] | |
| 3500 HD 6.6L Duramax – conventional | 20,000[8] | |
| 3500 HD 6.6L Duramax DRW – 5th-wheel hitch, Regular Cab | 32,000[8] | |
| 3500 HD 6.6L Duramax DRW – gooseneck, Regular Cab 2WD | 36,000[8] | Max Trailering Package; Sierra HD maximum |
Ratings depend on engine, cab, bed, axle ratio, drivetrain and packages; the exact figure for one vehicle is in GMC’s official trailering guide, and CarWhere’s Sierra HD towing capacity page breaks it down by configuration.
Related Sierra HD (2500HD/3500HD) research
See which trim and packages a Sierra HD (2500HD/3500HD) was ordered with.
Trim names on a used listing are not always right. The CarWhere build sheet decodes a GMC Sierra HD (2500HD/3500HD) VIN into the factory-ordered option codes (RPOs) on record — trim, engine, axle and the packages it was ordered with. $9.99, instant.
Frequently asked questions
What are the GMC Sierra HD trim levels?
For 2026 the Sierra 2500 HD comes as Pro, SLE, SLT, AT4, AT4X, Denali and Denali Ultimate. The 3500 HD offers the same lineup except AT4X, and AT4 is single-rear-wheel only.
How much can a Sierra 2500 HD tow?
GMC rates the 2026 2500 HD at up to 20,000 lb conventional with the Duramax and Max Trailering Package, and up to 22,390 lb with a 5th-wheel or gooseneck. The 6.6L gas V8 tows up to 16,000 lb conventional with 18- or 20-inch wheels.
What is the Sierra 3500 HD max towing capacity?
Up to 36,000 lb with a gooseneck, or 32,000 lb with a 5th-wheel hitch, on a Regular Cab 2WD dually with the Duramax and Max Trailering Package. Conventional towing tops out at 20,000 lb.
When did the Sierra HD get AT4X and Denali Ultimate?
Both arrived with the 2024 refresh. AT4X is a 2500 HD-only off-road trim with an available AEV Edition, and Denali Ultimate sits above Denali on both the 2500 HD and 3500 HD.
What changes for the 2027 Sierra HD?
GM adds an available Duramax 8.3L V8 rated at 555 hp and 1,230 lb-ft, uprates the 6.6L gas V8 to 412 hp, and quotes up to 38,000 lb of gooseneck towing. Pricing had not been announced.
Sources
Prices and equipment are as published by GMC for the model year shown; trim content changes between model years, so confirm a specific vehicle against its window sticker or build sheet.
- 2026 GM Fleet Guide (trucks: trims, equipment groups, engines, payload and trailering tables) — General Motors Fleet
- 2026 GMC Sierra 2500 HD trims and starting MSRPs — Cars.com
- GM raises the bar for Heavy-Duty power, capability and control headlined by all-new Duramax 8.3L Turbo-Diesel V8 engine (2027 HD) — GM Newsroom
- 2026 GMC Sierra 2500 HD trailering charts — GMC (General Motors)
- GMC Sierra — Wikipedia (secondary reference)
- Chevrolet Silverado — Wikipedia (secondary reference)
- 2026 GMC Sierra 3500 HD trailering charts — GMC (General Motors)
More GMC tools
- GMC tools & data hub
- GM engines guide (LS, LT, Duramax)
- GMC known issues by model
- GMC model histories
- Free GMC VIN decoder
- GMC window sticker by VIN
- GM options by VIN
- GM RPO option codes
- GMC specs by model
- GMC reliability
Independent reference compiled by CarWhere — not affiliated with or endorsed by General Motors. Chevrolet, GMC, Cadillac, Corvette, Duramax, Vortec and the model names are trademarks of their owner.