Hydraulic power-assisted recirculating ball with Digital Variable Steering Assist
Tire size
LT245/75R17E ALS
LT275/65R20E OOR
Wheel diameter
17 in
20 in
Wheel material
steel
aluminum
Wheelbase
141.6 in
158.9 in
Standard here, not on the base trim: Adaptive Cruise Control with Trailering (standard on AT4 and Denali), Digital Variable Steering Assist, Front and Rear Park Assist (now available on Pro and SLE trims)
Specifications
Source: manufacturer press kit
Brakes
Front brake diameter
355 mm
Front brake type
ventilated disc
Rear brake diameter
360 mm
Rear brake type
solid disc
Dimensions Exterior
Ground clearance
10.1 in
Overall height
79.7 in
Overall length
250.8 in
Overall width
81.8 in
Wheelbase
158.9 in
Engine Basics
Aspiration
naturally aspirated
Cylinder count
8
Engine displacement
6600 cc
Fuel injection system
gdi mpi
Engine type (full description)
6.6L V-8 gasoline or E85 FlexFuel
Valve configuration
Overhead-valve, two valves per cylinder, variable valve timing
Engine Output
Horsepower
401 hp
Torque
464 lb-ft
Fuel System
Fuel tank capacity
36 gal
Headroom
Front headroom
43.0 in
Second-row headroom
40.1 in
Legroom
Front legroom
44.5 in
Second-row legroom
43.4 in
Shoulder Room
Front shoulder room
66.0 in
Second-row shoulder room
65.3 in
Steering
Steering type
Hydraulic power-assisted recirculating ball with Digital Variable Steering Assist
Suspension
Front suspension type
Short long arms independent front suspension with torsion bars
Rear suspension type
Semi-elliptic, two-stage, multi-leaf springs
Tires
Tire size
LT275/65R20E OOR
Transmission
Final drive ratio
3.7
Transmission speeds
10
Transmission type
automatic
Weights
Curb weight (maximum)
7736 lbs
Curb weight (minimum)
6551 lbs
Gross vehicle weight rating
11350 lbs
Payload capacity
3407 lbs
Wheels
Wheel diameter
20 in
Wheel material
aluminum
Standard & optional equipment
Source: manufacturer press kit
Safety4 std · 0 opt
ABS and Stabilitrak electronic stability assist
Adaptive Cruise Control with Trailering (standard on AT4 and Denali)
Front and Rear Park Assist (now available on Pro and SLE trims)
6.6L V-8 gasoline or E85 FlexFuel engine (401 hp / 464 lb-ft)
Allison 10L1000 10-speed automatic transmission
Duramax 6.6L V-8 Turbo-Diesel engine (470 hp / 975 lb-ft)optional
Chassis2 std · 0 opt
Digital Variable Steering Assist
Short long arms independent front suspension with torsion bars
Cargo1 std · 1 opt
Trailer Brake Controller (standard across all trims)
Max Towing Package (NHT) – increases diesel conventional tow rating to 20,000 lb on qualifying configurationsoptional
Ranked by what shoppers ask about first; standard equipment before options.
Transcribed from the manufacturer's official press kit for the 2025 Sierra 2500HD. Confirm with the window sticker for a specific unit.
The cheapest ownership win
Insurers price the 2025 Sierra 2500HD very differently, and the gap between the best and worst quote on the same car and driver is usually larger than any option you are weighing on this page.
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Common questions about the Denali
Source: EPA, NHTSA and manufacturer press kits
What does the 2025 GMC Sierra 2500HD Denali add over the Pro?
Against the Pro, 3 features become standard that the Pro does not and 18 published specifications differ. Both lists are on this page, taken from the manufacturer's own press material.