Hevey or jamed y-axis

My k8200 experienced problems with the y axis a couple of weeks ago. It moved smoothly in one direction but was very heavy in the other. The problem seemed to lighten slightly when some electronic cleaner was applied, but it was still heavy.

I eventually bout a new motor and installed it, but the problem still remains.

How do i go about in troubleshooting this without destroying the printer?

Did you check the bearing opposite the motor.
Make sure it’s not freezing up.