Well, the very bottom of the shift ****(about 1/2") just about the actual shift lever unscrews. Given that the from a postion of looking down at the shifter, it may turn clockwise to lossen it. I can't remember for sure, but mine is always finger tight. I have to tighten it by hand about once a week. I don't want to over tighten it or risk damaging it with tools. I can imagine why yours would be so difficult. It plastic to plastic, so it shouldn't be that hard. Try turn it the other way. If that doesn't work, someone like me probably super glued it or something.