KiaPartsNow.com offers the wholesale prices for genuine 2020 Kia Optima parts. Parts like Auto Transmission Case are shipped directly from authorized Kia dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 1.6L - GAMMA, 2.0L - Theta 2, 2.4L - Theta 2. Body: Sedan - 4Door 5P.