2027 GMC Sierra 2500 HD: What Is New for Mobridge, SD

What Is New for the 2027 Sierra 2500 HD?

The 2027 order guide is the first edition, and it is short on ratings pages and long on equipment changes. Here is what it actually says, and nothing it does not:

• New engine codes for both V8s. The gas V8 with direct injection and variable valve timing is now code L8S, and the Duramax turbo-diesel V8 is now L6P. The guide prints no displacement, horsepower, or torque for either one, so neither do we.
• The Allison name on every 10-speed. Both transmissions, and the power take-off version for Pro and SLE, are listed as the Allison 10-speed automatic.
• 17-inch wheels and tires are gone. The 18-inch machined aluminum wheel with dark grey pockets is the base retail wheel on Pro, SLE, and SLT, on a new LT265/70R18E all-season tire with an 18-inch spare. Every 2027 truck leaves the plant on the wheel size the Max Trailering Package requires.
• GVWR up to 12,300 pounds. The top rating rises from 11,900 pounds on a Crew Cab long bed Duramax with Max Trailering, and the whole GVWR menu is re-cut for 18-inch wheels.
• Adaptive cruise control standard on all seven trims. It was an option on Pro, SLE, and SLT in 2026.
• Front Pedestrian and Bicyclist Braking replaces Front Pedestrian Braking inside the standard Sierra HD Pro Safety group.
• The Technology Package reaches the SLT. The 15-inch head-up display and Rear Camera Mirror can now be ordered on an SLT with the Preferred or Premium Package.
• E85 capability is dropped from the gas Pro, and the AT4X gets a new 18-inch wheel code.
• No new colors and no dropped colors. All eight carry over with the same trim rules; Coastal Dune and Glacier White Tricoat simply lose their "new" tag.

What did not change: the seven-trim ladder, cab and bed combinations, the Denali Ultimate's diesel-only rule, the Max Trailering Package's contents and prerequisites, the AT4X hardware, every trim package, and the trailering equipment. Read the full what-is-new breakdown.

The 18-inch machined aluminum wheel with dark grey pockets is the new base wheel for 2027.

Two V8s and the Allison 10-Speed

GM lists two V8s for 2027: a gas V8 with direct injection and variable valve timing, and the B20-capable Duramax turbo-diesel V8, both paired with an Allison 10-speed automatic. Output and trailer ratings for 2027 will be published in the GM Trailering Guide; until then, the figures you see anywhere for the 2027 truck are guesses.

Buy a 2026 now or order a 2027? · Duramax vs gas on the 2026 truck

Seven Trims for 2027

The ladder is unchanged: Pro, SLE, SLT, AT4, AT4X, Denali, Denali Ultimate. Pro and SLE come in Regular, Double, or Crew Cab; SLT and up are 4WD Crew Cabs. What moved for 2027 is standard equipment, and the table shows where.

AT4X in Coastal Dune: 35-inch mud-terrains, DSSV dampers, rear e-locker.

Denali Ultimate in Downpour Metallic at the Mobridge Marina.

SLT with the Technology Package: 15-inch head-up display and Rear Camera Mirror, new for 2027.

The AT4X keeps its 1.5-inch lift with Multimatic DSSV dampers, 35-inch mud-terrain tires, driver-selectable rear e-locker, skid plates, red recovery hooks, Obsidian Rush leather, 16-way massage seats, and the AEV Edition with stamped-steel bumpers. The Denali Ultimate keeps the Duramax as its only engine, Alpine Umber full-grain leather, 16-way massage seats, the Bose 12-speaker system, and the head-up display. The SLT is the trim that got more interesting: it is the volume trim on our lot, and for 2027 it can carry the head-up display and camera mirror that used to stop at AT4.

2027 trims: AT4X, Denali Ultimate, and the SLT · AT4 vs Denali on the rated 2026 truck

Towing for 2027: What Is Published and What Is Not

Straight answer: the 2027 order guide contains no trailer ratings, no payload, no curb weights, and no GCWR. Those pages will come with the 2027 GM Trailering Guide or a later edition of the order guide. Until then we do not print a 2027 tow number, and we suggest you treat any site that does with suspicion.

What is published is the equipment, and it carries over: the Z82 trailering package with receiver hitch, 7-pin and 4-pin connectors, integrated trailer brake controller, Hitch Guidance, and the trailering information label are standard on every trim. ProGrade Trailering with Hitch View and the In-Vehicle Trailering App is standard on SLT and up and available on the SLE with the Preferred Package. The Max Trailering Package is still Duramax-only and still not offered on the AT4X or any Double Cab.

If you need a rated truck for a trailer today, the 2026 Sierra 2500 HD is rated by GM up to 20,000 pounds conventional and 22,390 pounds gooseneck, properly equipped, and the full matrices by cab, bed, drive, and package are on the 2026 buyers guide. The trailering label in the driver door jamb of the specific truck is the final word for either model year.

2027 towing and Max Trailering: what is still unpublished · 2026 gooseneck math · 2026 fifth-wheel and Lake Oahe guide

Max Trailering Package and the 18-Inch Floor

The Max Trailering Package (NHT) is the same package for 2027: 3500 HD frame, 3500 HD rear leaf springs and shock package, 12-inch rear axle, spray-on bedliner, and the gooseneck and fifth-wheel prep with the hitch platform, stamped and capped bed holes, and bed-mounted 7-pin harness. It requires the Duramax and 18-inch or 20-inch wheels and tires, and it is not available on Double Cab models, the AT4X, the Lowered GVWR option, the bed delete, or the extra trailering wiring provisions.

The 18-inch rule is why the wheel change matters. In 2026 a Pro or SLE on 17-inch wheels had to step up a wheel size to take the package. For 2027 every truck already wears 18-inch or larger wheels, so the only prerequisite left is the engine. The rest of the capability menu is unchanged and lines up by trim like this:

The 2027 Max Trailering and GVWR post · Max Trailering explained on the 2026 truck

GVWR for 2027: 10,000 to 12,300 Pounds

GVWR is the truck's own maximum loaded weight: the truck, everyone in it, everything in the bed, and the hitch weight of the trailer. It is not the trailer rating and it is not GCWR, which is truck and trailer together. GVWR is the one capability number the 2027 guide does publish, and it moved up.

The 2026 maximum was 11,900 pounds, so the Crew Cab Duramax with Max Trailering gains 400 pounds of GVWR for 2027 and the AT4X gains 125 pounds with the gas V8 and 400 pounds with the diesel. A higher GVWR usually means more payload, but GM has not published 2027 curb weights, so we do not print a 2027 payload figure. Say "a higher GVWR ceiling" and stop there until the ratings land.

ProGrade Trailering and Cameras for 2027

The trailering technology carries over with the same availability pattern:

• Every trim: receiver hitch with 7-pin and 4-pin connectors, integrated trailer brake controller, Hitch Guidance, trailer sway control, hill start assist, and the trailering information label.
• SLT, AT4, AT4X, Denali, Denali Ultimate: ProGrade Trailering with Hitch View and the In-Vehicle Trailering App (pre-departure checklist, light test, maintenance reminders, trailer tire pressure and temperature with the accessory sensor set that monitors up to six trailer wheels). SLE gets the same with the Preferred Package.
• Sierra HD Pro Safety Plus on SLE and SLT: Trailer Side Blind Zone Alert, Rear Cross Traffic Alert, front and rear park assist; Crew and Double Cab add the Bed View camera, HD Surround Vision, and Trailer Camera Provisions. AT4 and up carry this content as standard.
• Available: an auxiliary trailer camera that mounts on the back of the trailer for a see-through view of what is behind it.

How the cameras and the app earn their keep at the Indian Creek ramp: read the Lake Oahe fifth-wheel and boat guide.

Ordering a 2027 for a Dakota Winter

A 2027 order placed this fall lands in the middle of calving season, so build it for January from the start:

• Every Duramax includes the engine block heater, exhaust brake, 220-amp alternator, and dual batteries. A winter grille cover is an available option with the diesel.
• Dual alternators (KHF), a 220-amp primary plus a 170-amp auxiliary, are available on all seven trims for plow lights, a bale bed, or a service body.
• Snow Plow Prep and Camper Package (VYU) adds the 220-amp alternator to gas trucks, raises the front axle rating, and adds skid plates, the dash grommet for the controller, and roof-light provisions. Requires 4WD; not with the F60 camper spring.
• Autotrac two-speed transfer case with an automatic 4WD mode on SLT and up; two-speed push-button case on Pro and SLE. The G80 automatic locking rear differential is standard on every trim except the AT4X, which has the driver-selectable e-locker.
• StabiliTrak with trailer sway control and, new for 2027, adaptive cruise control on every trim, which holds a following distance on a Highway 12 morning when the car ahead disappears into blowing snow.

Ordering a 2027 for a Mobridge winter · The 2026 winter and calving-check post

Cab, Bed, and Tailgate

The five cab and bed combinations carry over: Regular Cab long bed, Double Cab standard or long bed, and Crew Cab standard or long bed. Pro and SLE offer all of them; SLT and up are Crew Cab only, and the AT4X is Crew Cab standard bed only. The 2027 guide does not print dimensions, so the 2026 figures (8-foot long bed, 6-foot-9-inch standard bed, 81.9-inch width, 21-inch bed depth) should be treated as 2026 numbers until GM confirms them.

Tailgates: a standard tailgate on the Pro, the EZ Lift power-lock tailgate on SLE and up (Pro with the Convenience Package), and the MultiPro six-function tailgate on SLT and up, with the dealer-installed Kicker audio system available for it. Twelve fixed tie-downs rated 500 pounds each remain in every bed.

2027 Colors and Interiors: Nothing New, Nothing Dropped

All eight colors carry over with the same trim rules. Coastal Dune and Glacier White Tricoat, which debuted in 2026, are now simply part of the palette. The trip-ups are the trim rules, so here they are in full.

Interiors, unchanged: Pro in Jet Black vinyl or cloth; SLE in Jet Black or Dark Walnut and Slate cloth; SLT in Jet Black or Dark Walnut and Slate leather; AT4 in Jet Black with Kalahari accents; AT4X in Obsidian Rush full-grain leather; Denali in Jet Black Forge perforated leather or Atmosphere and Brownstone; Denali Ultimate in Alpine Umber full-grain leather.

The eight 2027 colors with their codes and trim rules.

Downpour Metallic, a Denali and Denali Ultimate color.

2027 colors: all eight carry over, and which ones your trim can wear

Safety and Technology for 2027

Sierra HD Pro Safety is standard on all seven trims and now includes Front Pedestrian and Bicyclist Braking alongside Forward Collision Alert, Following Distance Indicator, Automatic Emergency Braking, Lane Departure Warning, IntelliBeam, and Buckle to Drive. Adaptive cruise control joins the standard list on every trim.

• Pro Safety Plus (PQA) on Pro: front and rear park assist, Rear Cross Traffic Alert, Lane Change Alert with Side Blind Zone Alert, trailering mirrors.
• Sierra HD Pro Safety Plus (PED) on SLE and SLT: Trailer Side Blind Zone Alert, Rear Cross Traffic Alert, park assist, and on Crew and Double Cab the Bed View camera, HD Surround Vision, and Trailer Camera Provisions.
• Technology Package (CWM): Rear Camera Mirror and the 15-inch head-up display, now available on SLT (with the Preferred or Premium Package), on AT4 (with the Premium Plus Package), on Denali (with the Reserve Package), and standard on AT4X and Denali Ultimate.

Screens and audio carry over: a 7-inch display on the Pro; the 13.4-inch GMC Premium Infotainment with Google built-in and the 12.3-inch driver display on SLE and up; 6 speakers on Pro and SLE, Bose 7-speaker on SLT, AT4, and Denali, Bose 12-speaker on AT4X and Denali Ultimate; Wi-Fi hotspot capability and eight years of OnStar Basics on every truck.

How the 2027 Sierra 2500 HD Stacks Up

Until GM publishes the 2027 ratings, the honest comparison with the Ford F-250 and the Ram 2500 is an equipment comparison: engines and transmissions by name, standard driver assistance, trailering technology, and cabins. We keep the numbers off this page on purpose. The 2027 comparison post does the equipment-level comparison and points to the 2026 post for the rated truck.

2027 Sierra 2500 HD vs F-250 vs Ram 2500, before the numbers land · The rated 2026 comparison

2027 Sierra 2500 HD — Common Questions