I have a broken bolt on the trans cover. This bolt is where I am suppose to place a wire clip when I install the lights on the tractor. It has been that way as long as I can remember. What is the advice on fixing this issue? Should I try an extractor? Is this a through hole or a blind hole? If I have to drill out the broken bolt, what size drill bit do I use for this? The bolt is 3/8-16-3/4. I am not sure I have a 3/8-16 tap; might have to purchase one.