Eine schön klar gegliederte Anfrage. Keep it up.
Right off the bat: I'm completely unfamiliar with this transmission and I only quickly compared your information with some repair manuals. To me, it sounds like you might have a more fundamental problem.
Therefore, my questions are:
What spare parts were installed?
a) Are you sure those are the correct parts? According to the repair manuals, there are different versions (e.g., "stop" positioned at the top or top left), and the change occurred around the end of the 2000s. There might be compatibility issues, and it's possible that you installed the wrong part.
b) Are the used parts guaranteed to be in working order?
PS: For a more detailed guide, an email address would have been helpful

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Regards,
Sure.
Here is the translation of the text from German to English:
"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.