About 20 years ago I made a transmission controller that let you add paddle shifters to some cars with electronically controlled automatic transmissions. It was just a circuit board that would switch the solenoids on and off as you clicked up and down. So you could add a couple paddle shifter switches like this, then the transmission controller would let you manually change an automatic. It was neat at the time. A lot of cars have that now. ...even cars with CVTs for some reason.