2021 GMC Sierra 2500HD AT4
The 2021 GMC Sierra 2500HD AT4 is a 401-hp 6.6-liter turbocharged with a hydra-matic 6l90 6-speed automatic; final drive 3.73:1. or allison 10l1000 10-speed automatic; final drive 3.42:1 and four-wheel drive.
| Spec | Value |
|---|---|
| Engine | |
| Engine Type | 6.6L V-8 gasoline or E85 FlexFuel: cast iron block w/ nodular iron main caps, cast aluminum heads, 10.8:1 CR, OHV 2 valves/cylinder, VVT, direct injection. OR Duramax 6.6L V-8 Turbo-Diesel: cast iron block, cast aluminum heads, 16.0:1 CR, OHV 4 valves/cylinder, common-rail direct injection |
| Displacement | 6.6 L |
| Horsepower | 401 hp |
| Torque | 464 lb-ft |
| Valvetrain | Gas: overhead-valve, 2 valves/cylinder, variable valve timing (VVT). Diesel: overhead-valve, 4 valves/cylinder |
| Bore and Stroke | 103.25 x 98 (6.6L gas) / 103 x 99 (6.6L diesel) |
| Compression Ratio | 10.8:1 (gas) / 16.0:1 (diesel) |
| Injection Type | Direct fuel injection (gas) / Common-rail direct fuel injection (diesel) |
| Drivetrain | |
| Drive Type | 2WD or 4WD (all trims) |
| Transmission | |
| Transmission | Hydra-Matic 6L90 6-speed automatic (6.6L gas); final drive 3.73:1. OR Allison 10L1000 10-speed automatic (6.6L diesel); final drive 3.42:1 |
| 1st Gear | 4.03 |
| 2nd Gear | 2.36 |
| 3rd Gear | 1.53 |
| 4th Gear | 1.15 |
| 5th Gear | 0.85 |
| 6th Gear | 0.67 |
| Reverse | 3.06 |
| Final Drive | 3.73 |
| Fuel Economy | |
| Recommended Fuel | Regular unleaded or E85 FlexFuel (gas) / Ultra-low sulfur diesel (diesel) |
| Suspension | |
| Front Suspension | Short-long arm (SLA) independent front suspension with torsion bars |
| Rear Suspension | Semi-elliptic three-stage multi-leaf spring |
| Brakes | |
| Front Brake Calipers | Hydraulic power-assisted Hydroboost booster; four-wheel disc; ABS; StabiliTrak electronic stability control |
| Front Brake Disc | 14.0 x 1.6 in / 355 x 40 mm vented rotor (2500HD) |
| Rear Brake Disc | 14.1 x 1.3 in / 360 x 34 mm vented rotor (2500HD SRW) |
| Tires & Wheels | |
| Wheels Front | 17 in. steel or aluminum (Regular, SLE std); 18 in. steel or aluminum; 20 in. aluminum (Denali std) |
| Wheels Rear | 17 in. steel or aluminum; 18 in. steel or aluminum; 20 in. aluminum |
| Tires Front | LT245/75R17 (ALS) / LT265/70R17 (AT) / LT275/70R18 (AT) / LT275/65R20 (AT) |
| Tires Rear | LT245/75R17 (ALS) / LT265/70R17 (AT) / LT275/70R18 (AT) / LT275/65R20 (AT) |
| Dimensions & Weight | |
| Length | 235.5 in |
| Width | 81.75 in |
| Height | 79.94 in |
| Wheelbase | 141.55 in |
| Front Track | 68.1 in |
| Rear Track | 68.3 in |
| Ground Clearance | 10.19 in |
| Curb Weight | 2,500 lbs |
| Interior | |
| Headroom Front | 43.11 in |
| Headroom Rear | 39.88 in |
| Legroom Front | 44.53 in |
| Legroom Rear | 35.24 in |
| Shoulder Room Front | 66.06 in |
| Shoulder Room Rear | 64.88 in |
| Hip Room Front | 60.9 in |
| Hip Room Rear | 60.24 in |