Hello,
A doctor does not have "obligation of result" but "obligation of means": they must undertake everything according to the "rules of the art", even if finally, it does not work ...
A mechanic, on the other hand, has an obligation of result: he must, for the price of estimate, lead to what has been agreed, whatever the time and the difficulty finally necessary.
Your transmission must work.
Difficult on the other hand to take everything back, vehicle and money ...
I hope it helps you ...
Repair ?
Re: Repair ?
Oups, 2017 !! réponse probablement inutile...désolé