How to Change a Keyless Chuck on a DeWalt Battery Drill
- 1). Switch the setting of the drill's clutch and reduce it to the lowest range possible.
- 2). Open the chuck jaw as wide as you can and use a screwdriver to remove the screw that secures the chuck. Turn the screwdriver clockwise to loosen the screw.
- 3). Secure the end of a 1/4-inch or larger hex Allen wrench into the chuck. Strike the long end of the wrench counterclockwise with a hammer. This will loosen the old chuck and you can easily take it out.
- 4). Insert the new chuck where the old chuck was positioned. Turn the chuck counterclockwise until it is secured tightly in place (with a "keyless" chuck, you can hand-tighten the bit into place without using a chuck key).
- 5). Put back the screw that holds the chuck in place and tighten it well.
Source...