John Deere 125 riding mower. I just replaced the deck with a new one. Exactly the same setup as the old one. For some reason the blades are not fully disengaging now. The engage / disengage lever is moving harder than it used to. I'm wondering if it's just that there's a new belt that will stretch, or if there's some other kind of adjustment I need to make. Advice is much appreciated. Thanks !