I need advice on how to hook up a three speed standard overdrive transmission in my 62 1/2 ton Chevy truck-235 six. I plan to run wires to a flip switch in the cab instead of using the carb and governor. I would manually switch to overdrive as needed. The rest of the time I would use the standard three forward gears if I needed to pull something like a trailer or a hill. Any ideas or suggestions? The guy I bought the trans from said the flip switch will work...Thanks in advance for any ideas.