Lower unit oil

[Lostfisher]

Is it really all that important to use the name brand lower unit oil? I was told that ny 80-90 weight gear oil is just fine. If it is important to use the name brand stuff can it be thinned out with regular gear oil. I am not located near any saltwater either so i dont need to worry about any corrosive water getting in the the gearcase. What do you guys use/preffer for ur lower units.

 

[seahorse5]

Re: Lower unit oil

Any water, not just saltwater, can not only corrode your gears and bearings, but disrupts the lubrication properties of an oil.

Here is a test of lower unit oils and how they lubricate when water gets into the gearcase.

http://bwbmag.com/output.cfm?id=1891729&sectionid=308

 

[tx1961whaler]

Re: Lower unit oil

Any marine gear oil is fine for me. The marine oil is supposed to have additives that help if some water happens to get in the gearcase. Fresh water will kill a lower units's bearings almost as quickly as salt water will.

 

[ARC240]

Re: Lower unit oil

As said before, any MARINE gear oil is fine so long as it's the right weight (80W90, etc) and meets the standard requirement (ie. GL-4, GL-5 is what most outboards accept). Just remember not to mix different brands or weights of oils as different brands contain different friction modifier additives that will conflict with eachother if mixed. I personally use the Mercury HP GL-5, for the once or twice a year that I change the oil on my outboard, I figure it's worth it, works great and stands up to use...even when your lower unit seals are toast . Automotive gear oils do not contain the emulsifiers that marine lubricants do, so in the event that a seal does give out, the oil and water will mix with each other. Automotive gear oils will simply separate themselves from water, which can be quite damaging to transmission components such as clutches, gear selector shafts and especially gears and bearings.

 

[Sixmark]

Re: Lower unit oil

Water is your friend outside of the boat and drivetrain.....not inside it.

Quite frankly the major the difference between saltwater and freshwater is what it will smell like when the bearings burn up.

Marine grade oil is made for just that purpose, while you can use standard oil, the major issue is should you? NO

For me, the extra dollar you might have to spend is worth the peace of mind and protection, and then there is also saving money in the area of rebuilding a lower unit.

 

[5150abf]

Re: Lower unit oil

Concur, use LOWER UNIT OIL oil only, it has addative regular 80/90 doesn't to deal with water intrusion, the oil is $5, a new lower is $800-$1500.

 

[Brewman61]

Re: Lower unit oil

Curious why would you choose not to use the specified fluid? The cost difference is extremly minor, and the stuff should be readily available almost anywhere. While you might "get away" with your proposed solution, it's false economy at best.
Does it need to be "Name Brand"? Not necessairly.
Should it meet the specificed minimums? In my opinion, you betcha.

 

[rodbolt]

Re: Lower unit oil

7 posts
we still dont know what gearcase we are disscussing.
could use ATF,30wt,gl4 gl5 gl5 synthetic, yamaha HD or nerc HP.
depends on who made the case and when and what case.

it always helps to know whats being disscussed before the disscussion.