GMPartsGiant.com offers the wholesale prices for genuine 2004 Chevrolet Trailblazer EXT 4WD parts. Parts like Suspension/Front are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 4.2L, 8 Cyl 5.3L. Model Code: 4 DOOR, 4 DOOR EXT.