I have a Z axis growling only on rapids or least that is when it's noticeably loud.

Little back story first might help or shed light on what is the issue, the chiller developed a leak and was without coolant for an unknown amount of time before noticed. It wasn't noticed until the Z axis started to make noise.

Just looking for the first places to look, like ball screw assembly or z-axis motor: I search a little and found those a possible suspect items from previous posts. I guess I'm looking for ways to test or see what the issue is, so I can order some parts and get someone down here.

Thanks