GMPartsGiant.com offers the wholesale prices for genuine 2004 Chevrolet Silverado 2500 HD 4WD parts. Parts like Shift Control 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 6.6L Diesel, 8 Cyl 8.1L. Model Code: 2500 CREW CAB LONG BOX, 2500 CREW CAB STANDARD BOX, 2500 EXTENDED CAB LONG BOX, 2500 EXTENDED CAB STANDARD BOX, 2500 REGULAR CAB.