Taz 6 Z - Axis Motors Out of Sync

I seem to be having a problem with my z axis motors.

They were not at the same height so i cranked them by hand to the same height, and after some time they have gotten out of sync again.

How can I prevent this from occurring again?

Any help is greatly appreciated!

Check the motor couplers for a missing setscrew or damage. If it’s not that it may be the z carriage (x ends) are spaced too far in or out and are putting pressure on the leads crew.