GMPartsGiant.com offers the wholesale prices for genuine 2015 Buick Regal parts. Parts like Automatic Transmission Upper Valve Body are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 2.0L, 4 Cyl 2.4L. Model Code: CX 4 DOOR SEDAN, CXL 4 DOOR SEDAN, CXS 4 DOOR SEDAN.