GMPartsGiant.com offers the wholesale prices for genuine 2001 GMC Sierra 3500 4WD parts. Parts like Steering Pump Lines 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.