The Sierra HD and its twin, the Chevrolet Silverado HD, are designed for heavy towing and hauling. The 6.0-liter V8 and 6.6-liter turbodiesel are both mated to a six-speed automatic. The latter employs a heavy-duty transmission made by Allison. There is also a natural gas version of the 6.0-liter V8. The Z71 suspension tends to make the ride stiffer. Options include a snow plow preparation kit and a frame-mounted hitch for fifth-wheel towing. The cab offers a lot of storage space, and can easily serve as a mobile office. The top-trim Denali has a luxurious interior. Beginning with the 2016 model year, Apple CarPlay and Android Auto capabilities are added to the infotainment system.