My 1959 100-6 came with overdrive off. I refurbished the car without the overdrive since I didn't have the switches and other parts. It is now time to install it. Does anyone know the best way to clean it out and check it. I assume I can put power to it to check the solenoid. I an not sure how to best clean the inside or what solutions to use. It turns freely now but probably is real dirty inside. Any advice would be appreciated. I also need an arm for the throttle switch and a 5 point relay if anyone has one for sale.