The 2019 GMC Sierra HD is available in both the 2500 and 3500 models, each offered in four different trim levels; Base, SLE, SLT and Denali. The Sierra HD also comes in many different configurations. The 2500 versions come in double cab or crew cab, both with either a standard box or long box. The 3500 style mirrors those options but also offer the option of two extra wheels on the rear axles, useful for towing extra-heavy loads. Beyond that, both 2500 and 3500 are offered with either a 6.0L V8 making 360 horsepower and 380 pound-feet of torque or a 6.6L V8 turbodiesel making 445 horsepower and 910 pound-feet of torque. The 6.0 V8 engine is paired with a 6-speed heavy-duty automatic transmission, while the 6.6L V8 diesel gets the well-known Allison 1000 6-speed automatic transmission. All 2500 and 3500 HD Sierras come with the option of having 2-wheel or 4-wheel drive. Maximum tow ratings top out at 23,100 pounds on the 3500 when properly equipped. The Base Sierra trim is the entry point into the Sierra HD however still comes nicely equipped. Standard features include 17" steel wheels, automatic locking rear differential, StabiliTrak stability control system, hill start assist, chrome exterior trim, locking tailgate, bed rail protection caps, 7-inch touchscreen infotainment system with Apple CarPlay and Android Auto, 6-speaker audio system and a rear vision camera. The SLE trim adds a good amount of features including 17-inch aluminum wheels, chrome grille surrounds, LED cargo box lighting, EZ lift and lower tailgate, keyless entry, 4.2-inch driver information center, 8-inch touchscreen infotainment system, leather-wrapped steering wheel, digital steering assist and a trailering package with a trailer brake controller. Moving up to the SLT trim adds 18-inch chrome aluminum wheels, fog lamps, heated leather seats, power adjustable pedals, dual-zone climate control, and remote start. The top of the line Denali trim brings a sense of luxury to the HD pickup. Additional standard features include 20-inch chrome cast aluminum wheels, body-color bumpers and trim, signature Denali grille, spray-on bedliner, 8-inch driver information center, heated steering wheel, perforated leather seats, heated and ventilated power front bucket seats, wireless charging, Bose 7-speaker audio system and parking assist. Options across the Sierra HD range tend to be fairly practical, with items such as a longer axle ratio, dual alternators and off-road suspension across the checklist of options. However, more common items such as a rear seat entertainment system, a navigation system, wireless mobile device charging, a remote locking tailgate and a sunroof are also available on the Sierra HD.