My boss has an old Lockformer Vulcan 2900 table, lately we've been having a lot of issues with one of the pinion gears running along the axis. There's some sort of delay, where it isn't moving at the speed or distance that it should be, so at the end of the burn everything gradually becomes at least a half inch short.
We've spent hours going through our trial and error process, and are confident it's a mechanical issue in either the gear itself or the motor driving it, although we don't have the equipment or further knowledge we'd need to fix it. I'm hoping to either get some additional ideas to try and fix it ourselves, or at the very least find some suggestions of companies that will take a look at it for us.
Your description and the makers picture sounds and looks like a dual drive rack and pinion mechanism - correct?
You could try swapping the electronic driver modules between the two motor drives for the same axis to see if its a driver issue.
You could try swapping the cables from the electronic driver modules to the motor drives but this might change the direction of motion and this might be ok as a test without changing other settings to correct things.
The above should help isolate if it's an electronic issue.
You could swap the motor assemblies with a lot more effort to help isolate a mechanical problem.