Marine gear oil - is it different from regular gear oil?

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northernmerc

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I'm tired of paying nearly ten bucks a quart for marine gear oil to put in the leg of my outboards and inboard. Top quality 80 or 90 weight gear oil for automotive and industrial applications is two to three dollars. So, what's the difference, or is this just another rip off?

If the less expensive variety is good enough to lubricate gears in complex industrial gear boxes that cost tens of thousands of dollars, why won't it work just as well in simple boat legs?
 
Vic.S

Vic.S

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Re: Marine gear oil - is it different from regular gear oil?

My understanding is that they both comply with API GL5 but they tell us that the outboard stuff contains additional inhibitors to protect the gears in the event of water ingress.

Complex industrial gears and automotive rear axles generally are not at great risk from water ingress!
 
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robert graham

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Re: Marine gear oil - is it different from regular gear oil?

Yep, and I've thought the same thing but if you ever get a leak of water into your lower end maybe the inhibitors would be worth the price. I only change mine once a year so it's only a couple of dollars difference for the peace of mind. Good Luck!
 
bigskiohio

bigskiohio

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Re: Marine gear oil - is it different from regular gear oil?

i pay 16.00 a quart for merc syn. once a year,makes me feel better and its only once a year.
 
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northernmerc

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Re: Marine gear oil - is it different from regular gear oil?

Here's another interesting angle on this topic.

A quick surf around the net reveals that Yamaha and Tohatsu just call for any GL5 gear oil for their legs; they don't specify that it has to be "marine" gear oil.

I wonder what's different about Johnson or Merc gears and bearings? Are they not as good as Yamaha or Tohatsu gears that they need extra protection? Are the Asian manufacturers using a superior technology and/or a better grade of steel? (I somehow doubt it.) Merc even goes a step further and tells Merc owners to use their very expensive "Quicksilver" product to protect their product.:confused:
 
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wilde1j

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Re: Marine gear oil - is it different from regular gear oil?

High quality marine gears oils contain emulsifiers to help tolerate water intrusion better and they include antifoaming agents, which helps maintain lubricity in harsh, high RPM conditions, but hey. if you want to use cheap gear oil, it's your lower unit!
 
Bifflefan

Bifflefan

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Re: Marine gear oil - is it different from regular gear oil?

I thought it was an antifoaming agent that made the difference..
 
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freetime99

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Re: Marine gear oil - is it different from regular gear oil?

An oil rated as GL5 will do just fine. They all have anti-foaming additives. The rest is just packaging, price and the feel-good issue.
 
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jeff_smith_0423

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Re: Marine gear oil - is it different from regular gear oil?

freetime99 said:
An oil rated as GL5 will do just fine. They all have anti-foaming additives. The rest is just packaging, price and the feel-good issue.
Click to expand...

I whole heartedly disagree. The additive package in marine gear oil is designed to maintain lubricity in the event of water intrusion.

It's your gearbox - run whatever you want in it. Mine takes 11 ounces. I'll run the good stuff.
 
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Elbo

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Re: Marine gear oil - is it different from regular gear oil?

Marine gear oil will run 50% water and still lube.I ask my oem dealer the same question.
 
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northernmerc

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Re: Marine gear oil - is it different from regular gear oil?

ezeke said:
Some information here that might help: http://bwbmag.com/output.cfm?id=1891729&sectionid=308
Click to expand...

ezeke, thanks for that link. Very interesting, although I could not enlarge the graphs large enough to read them. The article makes the point that virtually all of the lubricants tested (including some that are not marine gear oils) ranked at or near the top in one or more tests - after dilution with water. Even the Walmart auto lube seems to have fared OK.

For peace of mind, given the cost of repairs if something goes wrong, I probably will continue running the marine gear oil in my Mercruiser stern drive unit. It needs one quart for a change. But I'm not going to worry about the small outboards if I happen to run out of the marine oil; they may get a name brand non-marine gear oil.
 
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