FordPartsGiant.com offers the wholesale prices for genuine 2005 Mercury Mountaineer parts. Parts like Rear Door Lock Controls 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.