Y-movement is not running smooth. loosing steps / position

I dont get the Y movement running smooth also. I added grease and increased voltage on the motor.
I also tried many times to optimize the alignments. I even tried to run th y-axis without the aditional mass of the heated bed and its support. Still no succes. I am out of options.

I solved it. I just needed to tighten the setscrew that connects the gearwheel to the motor better.
Now it runs fine. Silly me…