Ballscrew chattering. (noise)
Small segment worn out?
Passed to backlash compensation?
What is the ball screw lead? It is the linear distance traveled for each turn. If your ball screw lead is one inch, turning the nut one full rotation will result in exactly one inch of travel. If the lead is a half an inch, turning the nut one full rotation will result in half an inch of travel. You can measure your ball screw lead by the distance traveled for one complete turn. This information isn’t necessary for a repair estimate, but it is required for the manufacturing of a new nut & screw.