GMPartsGiant.com offers the wholesale prices for genuine 1989 Buick Lesabre Base Model parts. Parts like Automatic Transmission Case Channel Plate are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.8L. Model Code: 2 DOOR, CUSTOM 4 DOOR, LIMITED 2 DOOR, LIMITED 4 DOOR.