Boating season is almost upon us, so it’s time to get your vessel ready for the water. While it’s ideal to change lower unit fluids in the fall, many people choose to do it in the spring. That’s okay, as long as you change it, and as long as you use the proper gear lube.Why should I make a special trip to the store to buy marine gear lube? Can’t I use any old gear lube?
Marine gear lube, unlike automotive gear lube, is formulated to emulsify water. This serves two purposes:
- It provides consistent lubrication, keeping water away from moving parts
- It keeps the lower unit from freezing (yours didn’t freeze last winter, did it?)
Lower units contain hypoid gears (think ring and pinion, like a car differential) so they demand extreme pressure additives. The marine gear oil you choose will depend on the size of your marine engine. A small outboard will use a “simpler” formula than a larger, high-performance outboard that has much bigger gears and sees much higher loads.
So, can you use any old gear lube in your marine lower unit? If you want the best protection possible, and want your lower unit to last as long as your boat, then the answer is no. Consult your engine’s manual and look for the proper marine gear lube for your application.