MoparPartsGiant.com offers the wholesale prices for genuine 1984 Jeep J20 parts. Parts like Axle Housing, Rear are shipped directly from authorized Mopar dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 4.2L, 8 Cyl 5.9L. Transmission: 4-Speed Manual Transmission, Automatic Transmission.