Jeez, I got a new drive motor and 5 minutes later I was driving hard. You could really turn that new thing around with your fingers. Difficult, of course, but possible. The one that was stuck was so tight that there was no way to twist the finger (ring off). Even though everything worked fine when they were apart (gearbox and motor), but really when you put them together it didn't work.
Now, when I looked at that gearbox itself, I didn't find the so-called no fault/problem, that I recommend paying the 70e directly for the new engine and trashing the old one
Edit: I will open it one more time and see if I missed something, but yes, all the strollers seemed to be 100% fine.