GMPartsGiant.com offers the wholesale prices for genuine 2003 GMC Sierra 1500 2WD parts. Parts like Engine To Transmission Mounting are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 4.3L, 8 Cyl 4.8L, 8 Cyl 5.3L, 8 Cyl 5.3L Flex, 8 Cyl 6.0L. Model Code: 1500 CREW CAB LONG BOX, 1500 EXTENDED CAB LONG BOX, 1500 EXTENDED CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX.