I just bought a 2004 dakota slt, 3.7l v6 4x4. Occasionally when I back up there's a grinding sound from the rear right wheel, sometimes it's not so bad, but sometimes it's terrible, any suggestions?

 

Does the parking brake feel soft sometimes? You have disc brakes in the rear with parking brake shoes inside the hat. So in essence, it's like a drum and disc combined. Well the OEM parking brake shoes have a habit of the pad material falling off the metal backing. Weak glue I guess. That might be your issue. Pull off the brakes and look inside the hat.