I had an issue with mine and when I pulled out apart, found the angle drive housing had come loose.
A bit of a bigger to tighten, as something needsng needs to come off to get at the a few that holds it- so abandoned that plan, but as it turned out the unit spat a couple of other gears layer so had it fixed at the same time.
Seems to work ok, but a bit stiff and apparently I need to do big numbers one way and tenths the other. ..
Have some pics I think I can post later