Matt, on your chuck the rotary action of the outer body which acts on an internal screw; this in turn moves the threaded jaws in or out along a tapered surface. So, if any of the jaws, has jumped the thread, it will create a wedge and stop the chuck from moving. You can try to hold the drill with the chuck down and gently tap it with a small hammer (or the handle of a screw driver :-) and see if it will free the jaw. Otherwise, I would think it is time to replace the chuck. It is held on by a bolt right in the middle of the chuck. No electric parts are directly involved with this. Replacement parts and a diagram are available [http://www.ereplacementparts.com/ridgid-r84015-before-g0304-18v-max-speed-cordless-drill-driver-parts-c-7929_8250_8858.html|right here.] Hope this helps, good luck.