I'm not sure that I am an expert on the topic but I just took the chuck out of my DCD950 it also does not have a screw holding the chuck.
this is the video that I used to figure out how. My chuck wouldn't hold a bit so I had to use the channel locks. I opened the chuck all the way and then had to break loose the lock tight holding the chuck on with the channel locks. Hope this helps now I just need to find a replacement that doesn't cost an arm and a leg.