2018 GMC Sierra 3500HD Trims Comparison

For buyers interested in a basic heavy-duty truck, the base Sierra comes standard with a 6.0-liter V8 engine (360 horsepower and 380 pound-feet), a six-speed automatic transmission, 18-inch steel wheels, an automatic locking rear differential, xenon headlights, air conditioning, a choice of cloth or vinyl upholstery, a 40/20/40-split front bench with a fold-down center armrest, power door locks, manual crank windows, cruise control and a tilt-only steering wheel.

Also standard are a rearview camera, Bluetooth, a 7-inch touchscreen, a USB port, a four- (regular cab) or six-speaker sound system, and Apple CarPlay and Android Auto smartphone integration.

From the base Sierra on up, you also have your choice of engine. A turbocharged 6.6-liter diesel V8 (445 hp and 910 lb-ft) is available, also paired to a six-speed automatic transmission.

Many options are available for the base Sierra. Highlights include a remote locking tailgate, LED bed lighting, a 110-volt power outlet, satellite radio, and OnStar services with 4G LTE Wi-Fi.

For a slightly less bare-bones experience, the SLE offers an 8-inch touchscreen, 18-inch alloy wheels (single-rear-wheel models only), tinted rear windows, a remote-locking EZ-Lift tailgate, remote keyless entry, carpeted floor, a 60/40-split folding rear seat, full power accessories, a leather-wrapped steering wheel, a CD player, satellite and HD radio, and most of the base Sierra's options.

Further up the ladder is our recommendation, the SLT. Building on the SLE's equipment, the SLT adds foglights, power-folding mirrors, dual-zone automatic climate control, leather upholstery, power-adjustable and heated front seats, driver-seat memory settings, power-adjustable pedals, a tilt-and-telescoping steering wheel, an auto-dimming rearview mirror, remote ignition, and a 110-volt household-style power outlet.

For a luxurious take on your hard-working truck, go with the Denali. It adds a spray-in bedliner, a power-sliding rear window with defogger, front and rear parking sensors, a navigation system, wireless phone charging, a Bose audio system, an upgraded driver information display, upgraded interior trim, ventilated front seats and a heated steering wheel.

Many of the standard features on upper trims can be added at lower trim levels in grouped packages. Other optional highlights depend on trim level and include different axle ratios, a bed storage box, tonneau covers, trailering mirrors, a sunroof,  a gooseneck/fifth-wheel trailering prep package, a rear-seat entertainment system, and a Driver Alert package, which includes front and rear parking sensors, lane departure warning, forward collision warning and a safety-alert driver's seat.

Only available on the SLT is the All Terrain HD package, which includes 18-inch wheels, the Z71 off-road suspension, skid plates, front-and-rear parking sensors and a heated steering wheel. A separate Suspension package (available on the SLE and the SLT) offers hill descent control, skid plates, specially tuned shock absorbers and unique styling treatments.