I just bought a new coupler (2" Class 2) because the other one was all rusty and because they arent very expensive. Two questions: First, I notice the old one sat right on top of the frame and the holes line up. This one I have to raise about 1/2 inch off the top of the channel for the holes to line up. I don't think that makes a difference, but let me know if it does.<br /><br />The main question I have is, do you need to adjust the nut inside the coupler? I dont have it on the trailer yet but I put it on the ball just to see how it fits and it is pretty tight. I mean I cant swing it freely, I need to hold both pieces to swivel it, but its not too tight where I need to put a lot of pressure. The other one swivels quite freely but I never checked the nut on that. Just wondering how tight it is supposed to be and if you should grease it or the ball or anything on occasion.