Y axis grinding noise

HI Everybody

This is my first post, altough I have been reading/learning from cnc zone for a long time by now. I have a question about our large footprint wood cnc machine. I spent a lot of time trying to repair this problem but cant figure out what could be the issue. The machine makes a very stragne grinding / rezonance sound when cutting on the Y axis but only when it travels diagonal. I took apart the machine, I changed the ball screws on both axis, although one of them had balls fall out which I re installed it seemed to work fine at the time. Although on the right side axis (which seem to make the strange sound) it was harder to move the carriage by hand then the other side, there was more tesion.

I changed the stepper motors, I played with different resolutions and Amper settings. When I travel up and down on the y axis at any speed it seems to be ok but when force is applied the strage grinding sound starts .I try to attach a video so the sound can be heared. I hope somebody has experienced something like this or has an idea of some sort.

Any help is greatly appriciated

I am trying to post a link here with the video I am not sure if this work let me know if there is another way

https://drive.google.com/file/d/1Cbr...ew?usp=sharing

thank you

zoltan