GMPartsGiant.com offers the wholesale prices for genuine 2020 GMC Sierra 1500 Denali 4WD parts. Parts like Automatic Transmission Input Sun Gear Assembly are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 2.7L, 6 Cyl 3.0L Diesel, 6 Cyl 4.3L, 8 Cyl 5.3L, 8 Cyl 6.2L, 8 Cyl5.3L. Model Code: CREW CAB 5'8" BOX 1/2 TON, CREW CAB 6'6" BOX 1/2 TON.