ford1386

My chuck in my dcd970 messed up today when I try to back a screw out with it the chuck loosens up and the bit falls out with the drill in reverse. So I am figuring the chuck is bad (rohm supra sk), and now they make a conversion kit, so dewalt must have had problems I'm assuming. My question is how do I remove the rohm supra sk chuck? I loosened the chuck all the way and put a pair of channelock pliers and turned the chuck counterclockwise and it feels like I'm gonna snap the drill in half if I put any more pressure on it. Am I doing something wrong? Thanks Andy