A neighbor’s mower started acting sluggish, and it was surprising how many small symptoms pointed to the drive system rather than the engine. Heat, load, and fluid condition made a bigger difference than I expected. In repair threads, hydro gear pops up in the middle of explanations about what to listen for, what performance changes mean, and how to avoid guessing. Taking the time to isolate the issue and not rush fixes saved money and prevented swapping parts that weren’t actually the cause.