GMPartsGiant.com offers the wholesale prices for genuine 2001 GMC Sierra 3500 4WD parts. Parts like Intake Manifold Shield/Covers 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: 3500 CHASSIS EXTENDED CAB 161.5, 3500 CHASSIS EXTENDED CAB 185.5, 3500 CHASSIS REGULAR CAB 161.5, 3500 REGULAR CAB.