2026 GMC Sierra 2500HD Denali

Truck · 6.6L Duramax Turbodiesel V8 · 4WD

80/100

AutoVault's overall score, weighted for what a truck is actually for — performance, technology, comfort, reliability, safety and value.

Specifications

Engine	6.6L Duramax Turbodiesel V8
Horsepower	470 hp
Torque	975 lb-ft
0–60 mph	7.5 sec
Top speed	100 mph
Drivetrain	4WD
Seats	5
Combined MPG	15 mpg (13 city / 17 hwy)
Range	323 miles
MSRP	$84,495
Body style	Truck

The verdict

What's good

Denali interior quality and quietness set a high bar for work trucks
ProGrade trailering system with camera guidance simplifies hitching
Duramax diesel delivers refined, low-noise power at highway speeds
CarbonPro bed option offers exceptional dent and scratch resistance

What's not

Turning circle makes tight urban job sites frustrating
Denali premium pricing offers diminishing returns over SLT
Unladen ride remains bouncy despite improved suspension tuning
Diesel DEF fluid adds a maintenance variable many owners overlook

The engine

Duramax (L5P)

Turbo-Diesel V8

The same refined, low-revving diesel V8 that pulls heavy trailers with quiet, torque-forward composure, here paired with GMC's upscale Denali trim.

Produced by DMAX Ltd., the GM-Isuzu joint venture in Moraine, Ohio; the engine is mechanically identical to the unit in Chevrolet's HD trucks, as GMC and Chevrolet share GM's heavy-duty truck platform.

Though it wears a GMC badge, it is the very same L5P Duramax built alongside Chevrolet's, differing only in the truck it's installed in.
Isuzu engineered the original Duramax design, while GM owned the majority of the DMAX venture before buying it outright in 2022.
Roughly 90% of its peak torque arrives at just 1,550 rpm, giving the Sierra HD its relaxed heavy-tow character.

See the rest in AutoVault

The six sub-scores behind the 80 — performance, tech, comfort, reliability, safety and value
Market value today and year-by-year value history
All 6 trims with pricing
Studio photography — exterior, rear and interior
Side-by-side comparison with up to four cars

Open in AutoVault