GMPartsGiant.com offers the wholesale prices for genuine 2013 GMC Sierra 2500 HD 2WD parts. Parts like Antenna are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 8 Cyl 6.0L, 8 Cyl 6.0L Flex, 8 Cyl 6.6L Diesel. Model Code: CREW CAB 6'6" BOX 3/4 TON, CREW CAB 8' BOX 3/4 TON, EXTENDED CAB 6'6" BOX 3/4 TON, EXTENDED CAB 8' BOX 3/4 TON, REGULAR CAB 3/4 TON.