GMPartsGiant.com offers the wholesale prices for genuine 2019 GMC Sierra 2500 HD Denali 4WD 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: 8 Cyl 6.0L, 8 Cyl 6.0L Flex, 8 Cyl 6.6L Diesel. Model Code: 2500 CREW CAB STANDARD BOX.