A Makita cordless drill chuck is made by Jacobs. It is either a hand-tightening drill chuck or a chuck which uses a special wrench to tighten it. Both types are mounted on a threaded spindle and both are removed the same way. Jacobs chucks can be removed to clean or replace them with an upgraded model, and anyone with some do-it-yourself experience will be able to do this task.
Clamp the drill to a table. Tighten it down solidly. Allow the chuck to hang over the edge where it has been clamped.
Open the chuck jaws fully and unscrew the retaining screw which is set inside of the jaws with a screwdriver. Turn the screw clockwise to loosen it. This is a reverse-pitch screw and it must be turned the opposite way for removal.
Place a hexagonal wrench inside of the chuck, and tighten it exactly as you would tighten down a drill bit. The chuck arms will solidly grip the hexagonal pattern on the wrench when fully tightened. The wrench must be pointed out and to the left, parallel to the tables edge.
Strike the end of the wrench solidly with a rubber mallet. The chuck will loosen up from this action and can now be hand-turned off of the spindle.