Blog

A lower unit problem doesn't always start with a dramatic failure. Sometimes the first clue is a new noise, difficulty shifting, unusual vibration, or something you notice while changing the gear lube. The important part is figuring out whether the problem is actually inside the Mercury lower unit, something that can be repaired individually, or damage significant enough to consider replacing the complete gearcase. If you're looking for the basics of how a lower unit works, gear ratios, fitment, …