gear oil

例句：

1. 1. The car needs a new set of gear oil to keep it running smoothly.
   这辆车需要换新的齿轮油，才能让它运行顺畅。
2. 2. The mechanic replaced the old gear oil with fresh gear oil.
   机械师用新鲜的齿轮油替换了旧的。
3. 3. The engine needed some gear oil to keep it from overheating.
   发动机需要一些齿轮油，以防过热。