FordPartsGiant.com offers the wholesale prices for genuine 2003 Mercury Mountaineer parts. Parts like Front Doors, Hinges & Weatherstrips are shipped directly from authorized Ford dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 4.0L SOHC EFI, 8 Cyl 4.6L Romeo SOHC EFI. Transmission: 5-Speed Automatic Transmission 5R55S, 5-Speed Automatic Transmission 5R55W, 5-Speed Manual Transmission (M5R4), 6-Speed Automatic Transmission (6R80), 6-Speed Automatic Transmission 6R60.