2027 GMC Sierra 3500 HD: What Is New for Mobridge, SD

What Is New for the 2027 Sierra 3500 HD?

Short answer: a lot of equipment moved and almost no ratings were published. Here is what the 2027 information actually says, and nothing it does not.

• New codes for both V8s. The gas V8 is now L8S and the Duramax turbo-diesel V8 is now L6P. No displacement, horsepower, or torque is printed for either, so we do not print any either.
• The Allison name on every 10-speed, gas, diesel, and the power take-off version for Pro and SLE.
• The Duramax lives on 4WD models and the 2WD Regular Cab. A 2WD Crew Cab or Double Cab is a gas truck for 2027.
• Single-rear-wheel GVWR up 250 to 450 pounds, with a new ceiling of 12,700 pounds. The dually stays at 14,000.
• The 17-inch dually wheel and its tire are gone. Every 2027 dually rides on 18-inch wheels and LT235/80R18 tires.
• Adaptive cruise standard on all six trims, and Front Pedestrian and Bicyclist Braking replaces Front Pedestrian Braking inside standard Sierra HD Pro Safety.
• The Technology Package reaches the SLT, so the 15-inch head-up display and Rear Camera Mirror can be ordered on the volume dually trim for the first time.
• Smaller items: particulate filter manual regeneration with every Duramax, E85 dropped from the gas Pro, no color changes, and a separate chassis cab line.

What did not change: the six-trim ladder, the cab and bed combinations, the rule that a dually needs a long bed and the 14,000-pound rating, the Denali Ultimate's diesel-only status, Max Trailering and its Pro, 2WD, Regular Cab, dually-only prerequisites, every trim package, and the trailering hardware. Read the full what-is-new breakdown, or see what changed on the 2026 truck.

The 18-inch polished forged wheel: included content on SLE, SLT, and the Denali trims 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-compatible 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 they are, any 2027 horsepower or tow number you read is a guess, which is why you will not find one here.

The change worth circling is where the diesel lives. For 2027 the Duramax is listed on every 4WD model and on the 2WD Regular Cab long bed; the 2WD Crew Cab and Double Cab are gas-only. Around Mobridge that is mostly a footnote, because a truck that pulls a gooseneck off wet section lines in March gets bought as a 4WD anyway.

Buy a rated 2026 dually now or order a 2027? · Every 2027 change, line by line

Six Trims for 2027, and Which Ones Come as a Dually

The ladder is unchanged, with no AT4X on the one-ton. Pro comes in Regular, Double, or Crew Cab and is the only trim offered in two-wheel drive; SLE is 4WD in all three cabs; SLT and up are 4WD Crew Cabs. Dual rear wheels require a long bed and the 14,000-pound rating and are offered on every trim except the AT4, which stays single-rear-wheel only.

The SLT Crew Cab long bed dually is what most Mobridge outfits order, and the trim that gained most for 2027.

The 13.4-inch screen and 12.3-inch driver display carry over on SLE and up.

The trim to watch is the SLT. It is the dually most ranchers and contractors around here actually buy, and for 2027 it can finally add the 15-inch head-up display and the Rear Camera Mirror that used to stop at the AT4. That mirror is worth more on a one-ton than on any other truck, because a loaded stock trailer fills the inside mirror completely. The Denali and Denali Ultimate remain the comfortable end of the dually ladder. The AT4 is still the gravel-road single-rear-wheel truck, and it still cannot be ordered as a dually.

What the 18-inch dually wheel changes · The 2026 trim walk with full ratings

Towing for 2027: Not Published Yet

Straight answer: there are no 2027 trailer ratings. No conventional towing, no gooseneck, no fifth-wheel, no payload, and no combined weight ratings. They will arrive with the 2027 GM Trailering Guide. Until they do, we will not print a 2027 tow number, and we would treat any site that does with suspicion.

What is published is the hardware, and it carries over intact. The trailering package with the receiver hitch, the 7-pin and 4-pin connectors, Hitch Guidance, the brake controller, trailer sway control, and the trailering information label are standard on every trim. The gooseneck and fifth-wheel prep package is available on all six trims, and Max Trailering is unchanged.

What the 2027 GVWR numbers do and do not tell you · 2026 gooseneck math for a dually · Single rear wheel or dually?

Max Trailering and the Dually Packages

The Max Trailering Package on the one-ton is not the same animal it is on the three-quarter-ton, and people get this wrong constantly. On the 3500 HD it is a Pro-only, two-wheel-drive, Regular Cab, dual-rear-wheel, Duramax option, and it stays exactly that for 2027. It bundles the heavy-duty front spring and camper package, the 18-inch forged wheels and tires, and the gooseneck and fifth-wheel prep with the stamped bed holes.

One quiet consequence of the wheel change: that package always specified the 18-inch forged wheel and the LT235/80R18 tire, and now the whole dually lineup is on that size.

Flatbeds, bale beds, and service bodies · The 2026 package rules in full

GVWR for 2027: 11,250 to 12,700 Single Rear Wheel, 14,000 Dually

Gross vehicle weight rating is the truck's own maximum loaded weight: the truck, everyone in it, everything in the bed, and the hitch or pin weight of the trailer. It is not the trailer rating and not the combined truck-and-trailer rating. It is the one capability number published for 2027, and every single-rear-wheel model moved up 250 to 450 pounds.

Two things from that table. First, the 12,700-pound ceiling is up from the 2026 single-rear-wheel ceiling of 12,250 pounds on the same truck. Second, the dually did not move: 14,000 pounds in 2026, 14,000 for 2027, so nothing changed about the registration and plating question you already answered.

The honest limit of that number: a higher ceiling usually means more payload, but payload is the rating minus what the truck weighs, and GM has not published 2027 curb weights. Payload varies by equipment, and the door-jamb label on the specific truck is where the answer lives. One more trap: the rating codes were reused with different meanings between model years, so match the rating to the cab, bed, drive, and engine you are ordering.

GVWR, combined ratings, and trailer ratings explained · The 2026 payload tables

The 17-Inch Dually Wheel Is Gone

This is the change most likely to show up in your life, and the one nobody is talking about. For 2027 the 17-inch dually wheel, its caps, its chrome skins, and its tire are all deleted. Every 2027 Sierra 3500 HD dually rides on 18-inch wheels and LT235/80R18 all-terrain tires.

Why it matters at the tire shop: a dually carries six tires plus a spare, and a mixed yard has been stocking two dually sizes since the 18-inch forged wheel appeared on the Denali. From 2027 forward there is one size on the whole lineup, so rotations, chains, road-service calls in February, and the spare behind the seat all simplify to one part number. On ride, how a dually rides is still decided by how much weight is in the bed.

The single-rear-wheel ladder is untouched: 18-inch steel or aluminum on Pro, 18-inch aluminum on SLE and SLT with a 20-inch upgrade, and 20-inch wheels on AT4 and up. The 20s remain single-rear-wheel only, and there is still no 22-inch wheel on the 3500 HD.

The full 18-inch dually wheel and tire guide

ProGrade Trailering and Cameras for 2027

The trailering technology carries over, which on a dually is the difference between backing a 40-foot gooseneck into a corral gate on the first try and getting out twice to look.

• Every trim: receiver hitch with 7-pin and 4-pin connectors, the integrated trailer brake controller, Hitch Guidance, trailer sway control, hill start assist, an HD rear vision camera, and the trailering information label in the door jamb.
• SLT and up: ProGrade Trailering with Hitch View and the in-vehicle trailering app, which holds a pre-departure checklist, a light test you can run alone, maintenance reminders per trailer, and trailer tire pressure with the accessory sensor set. The SLE gets the same with the Preferred Package.
• Sierra HD Pro Safety Plus on SLE and SLT: Trailer Side Blind Zone Alert, which extends coverage down the length of the trailer, Rear Cross Traffic Alert, and park assist. Crew and Double Cabs add the Bed View camera, HD Surround Vision, and trailer camera provisions.
• Available: an auxiliary camera that mounts on the back of the trailer for a see-through view, and the Rear Camera Mirror, orderable on an SLT for the first time. On a dually, power trailering mirrors come with the territory, and the extra track width of the rear fenders is exactly why surround view earns its money in a tight feedlot alley.

How the cameras earn their keep on a working deck: read the hotshot and harvest guide.

Ordering a 2027 for a Dakota Winter

An order placed this fall typically builds and ships over the winter, which means it can land in the middle of calving. Ask us for the current order-bank window, then build the truck for January from the start rather than adding pieces in March.

• Every Duramax includes the block heater, exhaust brake, 220-amp alternator, and a 730 cold-cranking-amp battery, with the winter grille cover available. The exhaust brake is the piece flatlanders underestimate: coming down the river breaks with a loaded gooseneck, it keeps you off the service brakes.
• Dual alternators, 220-amp plus 170-amp, are available on all six trims for plow lights, a bale bed, or a service body.
• Snow Plow Prep and Camper is on all six trims for 2027, duallys included. It adds the 220-amp alternator to a gas truck, raises the front axle rating, and adds skid plates, the dash grommet, and roof light provisions. It requires 4WD and is not combinable with the heavy-duty front spring package.
• Transfer cases: two-speed push-button on Pro and SLE, Autotrac with an automatic 4WD mode on SLT and up, and the automatic locking rear differential standard on every trim.
• New for 2027, adaptive cruise on every trim, which holds a following distance on a Highway 12 morning when the pickup ahead disappears into ground blizzard. Upfitter switches, high idle, and the vehicle module are still on the menu for a plow truck or a bale bed.

The winter and snow plow prep walkthrough · Timing an order against calving and haying

Cab, Bed, Tailgate, and the 2027 Chassis Cab

The cab and bed combinations carry over exactly: Regular Cab long bed, Double Cab long bed, Crew Cab standard bed, and Crew Cab long bed. There is still no Double Cab standard bed, and any dually is a long bed. No 2027 dimensions have been published, so treat every width, length, and bed measurement you see as a 2026 number.

Tailgates are unchanged: the standard tailgate on the Pro, the EZ Lift power-lock tailgate on SLE and up, and the MultiPro six-function tailgate standard on AT4 and up and available on the SLT. The Kicker audio system, bed step lights, bed covers, the CornerStep bumper, the in-bed outlet, and twelve tie-downs rated 500 pounds each are still on the list.

The chassis cab, documented for 2027

If your next truck is going under a flatbed, a bale bed, or a service body, the 2027 chassis cab is its own truck line, and this is the first year we have its specification in hand:

• Trims and cabs: Pro on all models, SLE on 4WD models; Regular or Crew Cab; 2WD or 4WD.
• Rating: 14,000 pounds on every chassis cab model. There is nothing else on the menu.
• Underneath: a wide-track rear axle and a fully-boxed hydroformed front frame with an open C rear section for a body builder.
• Engines: gas V8 standard, Duramax available, each with the Allison 10-speed, plus power take-off with the diesel and 4WD.
• Fuel: a 40-gallon rear tank standard, or 63.5 gallons across two tanks with the Duramax.
• Wheels: the same 18-inch wheels and LT235/80R18 tire as the pickup dually.
• Equipment: the Convenience, Heated, and Remote Start packages, Snow Plow Prep, heavy-duty front springs, dual alternators, upfitter switches, high idle, and a fleet-order Ambulance, Fire, and Rescue package on the Regular Cab. Adaptive cruise and Sierra HD Pro Safety are standard.

What it does not publish: cab-to-axle lengths, wheelbases, payload, and trailer ratings. Those come from the body builder and the GM upfitter guide. Bring us the bed you intend to mount and we will work the cab-to-axle with the upfitter before the order goes in.

Flatbeds, bale beds, and service bodies on the 2027 chassis cab

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 arrived for 2026, are now just part of the palette. The trip-ups are the trim rules, so here they are in full.

Interiors, unchanged: the Pro in Jet Black vinyl or cloth, the SLE in Jet Black or Dark Walnut and Slate cloth, the SLT in Jet Black or Dark Walnut and Slate perforated leather-appointed seats, the AT4 in Jet Black with Kalahari accents, the Denali in Jet Black Forge leather or Atmosphere and Brownstone, and the Denali Ultimate in Alpine Umber full-grain leather. A note from the lot: vinyl in a Pro is not a punishment on a calving truck, it is a hose-out floor.

Volcanic Red Tintcoat: an SLT and AT4 color the Denali trims cannot wear.

Summit White is the no-charge color on every trim.

Safety and Technology for 2027

Sierra HD Pro Safety is standard on all six trims and now includes Front Pedestrian and Bicyclist Braking alongside Forward Collision Alert, the Following Distance Indicator, Automatic Emergency Braking, Lane Departure Warning, IntelliBeam, and Buckle to Drive. Adaptive cruise joins that standard list on every trim for 2027.

• Pro Safety Plus on the Pro: park assist, Rear Cross Traffic Alert, Lane Change Alert with Side Blind Zone Alert, and trailering mirrors. Not with Max Trailering or the bed delete.
• Sierra HD Pro Safety Plus on SLE and SLT: Trailer Side Blind Zone Alert, Rear Cross Traffic Alert, and park assist, plus the Bed View camera, HD Surround Vision, and trailer camera provisions on Crew and Double Cabs.
• Technology Package: the Rear Camera Mirror and the 15-inch head-up display, now available on the SLT with the Preferred, Premium, or Texas Premium Package, on the AT4 with Premium Plus, on the Denali with the Reserve Package, and standard on the Denali Ultimate.
• Screens and audio, unchanged: 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; Bose 7-speaker on SLT and Denali and Bose 12-speaker on the Denali Ultimate; Wi-Fi hotspot capability and eight years of OnStar Basics on every truck.

Adaptive cruise being standard is the change we expect people to notice first, and it is worth the most on a Pro or SLE. A work truck that runs Highway 12 to Selby or US 83 to Pierre several times a week now holds its own following distance without a package.

How the 2027 Sierra 3500 HD Stacks Up

Until GM publishes the 2027 ratings, an honest comparison against the Ford F-350 and the Ram 3500 is an equipment comparison, not a numbers comparison. We keep competitor weight figures off this page on purpose, because comparing a published 2026 number to an unpublished 2027 one is how bad advice gets made.

On equipment for 2027, the Sierra 3500 HD brings an Allison 10-speed behind both V8s, adaptive cruise standard on every trim, the full trailering suite standard, 18-inch wheels and one tire size across the dually lineup, and a head-up display now reachable on the SLT. Where it does not play: there is still no one-ton AT4X, and a dually is never an AT4. For the number-for-number comparison, use the 2026 trucks, where every figure on all three brands is published.

The rated 2026 dually-to-dually comparison · How the 2026 truck compares

2027 Sierra 3500 HD — Common Questions