I have a 2006 SLT Ram with the 5.7L Hemi. It of course has 4wheel anti-lock disc brakes. Some time ago it started chattering a bit when I hit the brakes. It has gotten much worse. Last summer I replaced the front dics and pads but the chattering continued. I recently looked at the rear discs and whole it probably needs new pads pretty soon, there is no evidence of the discs being warped or anything like that. The truck rides okay so it's not like I have a warped wheel. Is the something I'm missing here? What else could cause such terrible chattering? I know the anti-lock function is all computer controlled. Is there some kind of brake modulator or something that could be doing this?

 

I would pull the rears, and have a look at the pads. If they are riveted, there will still be some pad left when the rivets start digging in to the rotor. Usually the back side will start getting munched up first.....

 

A likely cause of your chattering is worn anti-rattle springs on the brake pads. Replace the springs when you put in new pads and hopefully this solves your problem.
Worst case is that the brake pads are the wrong size and moving around in the caliper. Do you have spongy brakes? Chattering with spongy brakes is rare, but could be sign of wrong size pads or improper installation.