I have a 2002 Kia Optima and the reverse is out. It also shifts hard at high rpms. I took it to Auto Zone and got the codes ran and it is the shift solenoids. I can't remember the codes off hand, but I was wanting some feedback on what this may cost or how much work it involves. It started one day when I rinsed off my engine and when I left the car wash, it started acting up.