Threadloc is an adhesive that will keep your screws from vibrating out. You can get it at any hardware or automotive store. It comes in a tube or a stick. I like the stick because it is not as messy. It also comes in multiple colors. Get the blue stuff. Use a small dab of it on any screw that goes into metal parts. If the screw goes into a plastic part like the diff case, do not threadloc it.