MoparPartsGiant.com offers the wholesale prices for genuine 2015 Jeep Grand Cherokee parts. Parts like Gear Shift Motor are shipped directly from authorized Mopar dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.0L Diesel, 6 Cyl 3.6L, 8 Cyl 5.7L, 8 Cyl 6.4L. Transmission: 8-Speed Automatic Transmission.