2012 GMC Sierra 3500: What's New, Specs & Features
Last updated August 13, 2026
The biggest change for the 2012 GMC Sierra 3500 is that its 6.0-liter gasoline V8 gains E85 FlexFuel capability across all four trims. This is otherwise a targeted update, with new towing aids and several trim-specific equipment changes rather than a redesign.
About the 2012 GMC Sierra 3500
GMT900-era Sierra HD, second model year after the major 2011 heavy-duty chassis and powertrain overhaul
GMC positioned the Sierra 3500HD as its maximum-duty pickup for large trailers, fifth-wheel or gooseneck loads and heavy payloads, with a more comfort-focused presentation than a basic commercial truck. Its core identity combined a fully boxed heavy-duty frame, V8 power, integrated towing controls and multiple cab and bed configurations. Denali extended the same one-ton capability into a luxury-oriented crew-cab truck.
The 2012 Sierra 3500 ranges from the straightforward Work Truck to the comfort-focused SLE and SLT, with Denali combining heavy-duty hardware and the richest cabin. Every trim has a gas or turbo-diesel V8 with a six-speed automatic, while upper trims add features such as heated leather seats, Bose audio and power-adjustable towing mirrors. Denali stands out with cooled front seats, a heated steering wheel, a rearview camera and rear parking sensors.
What changed, by category
2012 GMC Sierra 3500 specs and features by trim
| Feature | ||||
|---|---|---|---|---|
| Engine | V8, Flex Fuel, 6.0 Liter / V8, Turbo Diesel, 6.6 Liter / V8, Turbo Dsl, 6.6L | V8, Flex Fuel, 6.0 Liter / V8, Turbo Diesel, 6.6 Liter / V8, Turbo Dsl, 6.6L | V8, Flex Fuel, 6.0 Liter / V8, Turbo Dsl, 6.6L | V8, Flex Fuel, 6.0 Liter / V8, Turbo Diesel, 6.6 Liter / V8, Turbo Dsl, 6.6L |
| Transmission | Automatic, 6-Spd HD w/Overdrive / Auto, 6-Spd Allison w/OD | Automatic, 6-Spd HD w/Overdrive / Auto, 6-Spd w/OD | Auto, 6-Spd w/OD | Automatic, 6-Spd HD w/Overdrive / Auto, 6-Spd w/OD |
| Drivetrain | 4WD | 4WD | 4WD | 4WD |
| Fuel Type | Flexible Fuel / Diesel | Flexible Fuel / Diesel | Flexible Fuel / Diesel | Flexible Fuel / Diesel |
| Horsepower | 322–397 hp | 322–397 hp | 322–397 hp | 322–397 hp |
| Torque | 380–765 lb-ft | 380–765 lb-ft | 380–765 lb-ft | 380–765 lb-ft |
| Max Towing | 13000–16500 lb | 13000–18000 lb | 13000–17000 lb | 13000–18000 lb |
| Rear Legroom | 34.3–39 in | 34.3–39 in | 39 in | 34.3–39 in |
| Seats | 3–6 | 5 | 5 | 3–6 |
| Doors | 2–4 | 4 | 4 | 2–4 |
| Alarm System | ||||
| Rear Parking Sensors | ||||
| Rear View Camera | ||||
| Alloy Wheels | ||||
| Fog Lights | ||||
| Heated Mirrors | ||||
| Power Moonroof | ||||
| Power Mirrors | ||||
| Privacy Glass | ||||
| Bluetooth | ||||
| Front DVD Entertainment System | ||||
| Navigation System | ||||
| Rear DVD Entertainment System | ||||
| Satellite Radio | ||||
| Subwoofer | ||||
| USB Ports | ||||
| Auto-Dimming Interior Mirror | ||||
| Cooled Seats | ||||
| Dual Power Front Seats | ||||
| Dual-Zone Climate Control | ||||
| Heated Front Seats | ||||
| Heated Steering Wheel | ||||
| Integrated Garage Door Opener | ||||
| Leather Seats | ||||
| Leather-Wrapped Steering Wheel | ||||
| Memory Driver's Seat | ||||
| Power Adjustable Pedals | ||||
| Power Windows | ||||
| Remote Start | ||||
| Tilt Wheel | ||||
Frequently asked questions
Was the 2012 GMC Sierra 3500 redesigned?
No. The 2012 Sierra 3500 carries over the heavy-duty frame and gas/diesel V8 lineup introduced with the major 2011 overhaul, while adding targeted powertrain, towing-aid and equipment updates.
What is the biggest change to the 2012 GMC Sierra 3500?
The biggest change is E85 FlexFuel capability for the 6.0-liter gasoline V8 across all four trims. The turbo-diesel V8 remains part of the lineup.
What towing aids were added to the 2012 GMC Sierra 3500?
Single-rear-wheel 2012 Sierra 3500 trucks add trailer-sway control and hill-start assist. Trailer-sway control helps settle unwanted trailer movement, while hill-start assist helps keep the truck from rolling backward when starting on a slope.
What became standard on the 2012 Sierra 3500 Denali?
The 2012 Sierra 3500 Denali makes cooled front seats, a heated leather-wrapped steering wheel and a rearview camera standard. Its gasoline version also gains E85 capability, and single-rear-wheel models receive the new towing aids.
How did the 2012 Sierra 3500 Work Truck change?
The 2012 Sierra 3500 Work Truck adds standard cruise control and vertical camper-style towing mirrors. Gas models also gain E85 capability, while single-rear-wheel versions add trailer-sway control and hill-start assist.