If using a dry rub, rub meat all over, Wrap in plastic. Place onto a sheet pan (to catch leaks!) and place into refrigerator overnight.
Uncover and discard plastic wrap and place the meat into the slow cooker.
Pour enough root beer into the slow cooker until the meat is just covered. Turn onto low and cook for 6-8 hours or until meat shreds easily with a fork.
Drain the root beer. Discard the bones and excess fat. Shred the meat and return to the slow cooker.
Gently fold in just enough BBQ sauce to lightly coat the meat. Server immediately or keep on the warm setting for up to an hour.
Serve with buns, coleslaw and extra bbq sauce on the side.