The knock could be part of the suspension and/or a problem with how the motor was put in. The tech should be able to return to fix this problem relatively easily.
No, you should not expect that many service calls in the first year. You can contact GE directly and explain that you have a concern that the tech did not re-assemble the washer correctly and that you are feeling that the machine may have permanent damage now.
If you persist with politely asking for their superior, you may suceed in having them exchange the washer or (at the very least) warranty the washer for an EXTRA year.
If they tell you no you use these magic words are -
"Thank you for you help. I understand that you may not have the authority to approve an exchange. May I have the name and telephone number of your superior so that I can discuss it with them?"
Get their name and keep using it. This is so they know that they will be mentioned by name to the the superior. At some point, someone decides that they either don't want to explain this to their boss or they feel that they are too important to spend more time on it. It is very effective.
You now have two seperate question opened. Please stay with one so that we can see everything together. It gets very confusing going back and forth.