Okay, the user wants me to translate "gear-boxes" into Thai. Let me check the rules again. The first rule says to translate all content into Thai. The second rule mentions if the content is already in Thai, leave it as is. The third rule says to provide only the translation without explanations.
So, "gear-boxes" is in English. I need to translate it. The correct Thai term for gear-boxes would be "กล่องเกียร์" which is the standard translation. I should make sure there's no typo and that it's the most commonly used term. Since the user specified to output only the translation, I'll just write "กล่องเกียร์" without any extra text. Let me confirm once more that there's no explanation or additional content. Yep, that's all.