trying to figure out what I'm doing wrong here. Unfortunately, hit a rock today with mower, shut right off. When I got it to start again, it's making an awful metal clanking noise. I look underneath and the blade is pretty loose. Here's the problem - when I try to spin that nut off (either tighten or loosen), all it does is spin the spindle? so it seems there's no way to actually apply any pressure in either direction to the nut? anyone have any ideas here? I see the 2 holes on the blade to theoretically hold it in place into the spindle, but there's nothing on the other side for them to "latch" into (maybe they ripped off from the force of hitting the rock)?