You can often get rid of some issues by taking a look inside the knob assembly (the plastic or leather part underneath the knob) and observing the mechanism within.
For example, I clamped a 1 mm sheet of metal to the longitudinal axis to eliminate any play in that area.
I also put something in between the cross axle (where the plastic cross is attached) to reduce the play.
Unfortunately, the rubber grommet at the front of the gearbox (which is part of the shift cable) has some play – but there are two versions available, and they aren't sold separately.
The cable has no slack, but that's because of the redirection mechanism located at the front of the gearbox

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http://www.luxus-wg.de/~martin/auto_bilder/schalt.jpg
Okay, please provide the German text you would like me to translate into English. I will only provide the translation.