GMPartsGiant.com offers the wholesale prices for genuine 1989 Oldsmobile Cutlass Supreme Base parts. Parts like Automatic Transmission Case & Related Parts are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 2.3L, 4 Cyl 2.5L, 6 Cyl 2.8L, 6 Cyl 3.1L, 6 Cyl 3.3L. Model Code: 2 DOOR, 4 DOOR.