<p>This GMC Sierra 2500HD available WiFi has a powerful Gas/Ethanol V8 6.0L/366 engine powering this Automatic transmission. KBB.com Brand Image Awards. WORK TRUCK PREFERRED EQUIPMENT GROUP includes standard equipment, WHEELS, 17 (43.2 CM) STEEL includes 17 x 7.5 (43.2 cm x 19.1 cm) steel spare wheel. (STD), TRANSMISSION, 6-SPEED AUTOMATIC, HEAVY-DUTY