W126 Sliding roof motor question
 

I tried the search, but did not find what I needed.

I have the sunroof motor out for cleaning of the tubes. The threaded shaft with the large nut is very loose in and out ( push-pull on the shaft). There is maybe 4-6mm of clearance. There is no perceptible clearance in the rotational direction.
The reason for the maintenance is that the motor failed to move the roof panel, and a loud burping/ buzzing noise was coming from the trunk.
I assume ( ouch!) that the noise is the clutch slipping, or the gear stripping over the cable.
Is that clearance excessive?
Can it be adjusted?
Am I better off with a junkyard replacement motor?

Thanks,
If there is a thread where this has been discussed, please just post a link.