I pulled the lower unit drain screw and drained my gear oil. Then I went to reinsert the drain screw and it will not go in. There is a piece of metal in the way. It looks like it moves when I change from Neutral to Forwardto Reverse. I can not get the gear oil drin screw back in. What is going on? What can I do to fix it? (The drain screw is about 1/2" of threads then a 3/4" smooth shaft on the end of it.) Is that normal, too?<br /><br />Thank you for your help.