Y axis squeaks in one direction

I have a Summit VS242B CNC knee mill. Today, when I started it up, there is a noticeable "squeak" only when I move the Y axis towards me. It squeaks when I move the Y axis manually also. There does not seem to be any drag on the axis. Any suggestions?

Check the coupler that connects the Y axis motor to the screw; it sounds like it might be loose.

Thanks for the info Andrew. I will check it out