Lower Unit Gear Lube

igblack87

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My marina sold me Gearcase HD lube. Can I use this in my 130hp v4?

I read on the back it’s specific for v8’s & v6’s...the regular 80w90 is for anything less than 250hp.

thoughts, thanks!
Ian
 

seasick

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It may be a bit of overkill but I don't think it will do any harm.
 

DennisG01

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I don't know what year your 130HP is, but you'll want to find out (owner's manual probably tells you) whether your lower unit bearings requires GL4 or GL5 gear lube. Then find out what that GC HD lube is. You can also check (download) an owner's manual for one of the V8's you're referring to and what type of gear lube it requires. If your GC used GL4, you can't use GL5.
 

wspitler

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The Yamaha HD is a GL-5 rated lube and I'm told that because of a higher level of additives it can be corrosive to "yellow" metals like bronze bushings. According to Yamaha factory, they recommend you use only regular Yamaha lower unit oil which is GL-4 rated. There are a number of discussion threads related to this topic. Agree with seasick, but I did use GL-5 once before I researched it and it seemed to get black quicker. There are numerous discussions, most about gear case synchronizers in cars.
 

DennisG01

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I have a 2001 saltwater series 2
You should double check for your own assurance, but I would imagine that your LU would use a GL4 like mine does. If so, and Bill is correct on the HD lube being GL5... case closed.

If you would like to use a synthetic gear oil that can better withstand water intrusion, you can use the Merc Hi-Perf gear oil. It is a GL4 oil.

But again, you should really do your own research to make sure.
 

SkunkBoat

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IMHO...use a generic " Hypoid 90W outboard lower unit gear oil"...Lubrimatic, Walmart, Sierra, West Marine...meet or exceeds GL-5....$10 a qt...don't go crazy, you're going to change it every season.

If you operate very cold, like Minnesota cold, then 80W90
 
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Fishtales

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I'd go by the manufacturers specs. If different, buy what is required.
 

DennisG01

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IMHO...use a generic " Hypoid 90W outboard lower unit gear oil"...Lubrimatic, Walmart, Sierra, West Marine...meet or exceeds GL-5....$10 a qt...don't go crazy, you're going to change it every season.

If you operate very cold, like Minnesota cold, then 80W90
But... GL5 is not better than GL4 and GL5 is NOT backwards compatible with GL4 - it is different. It's also not about "hypoid" - that's simply the shape of the gears - it's the bearings that are important. Or, at least, that's what I've always known about these things.

EDIT: Forgot the word "NOT"
 
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SkunkBoat

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But... GL5 is not better than GL4 and GL5 is NOT backwards compatible with GL4 - it is different. It's also not about "hypoid" - that's simply the shape of the gears - it's the bearings that are important. Or, at least, that's what I've always known about these things.

EDIT: Forgot the word "NOT"
Yes "Hypoid" just refers to the shape of the gears

IMHO, with the exception of some very old motors that used ATF.... ITS JUST GEAR OIL. All of the "Lower unit" oils will meet or exceed mfg requirements.
He's got a 20 year old motor...he doesn't need $25 oil.

Although, the CEO of Yamaha does need to gas up his Lamborghini....;)
 

DennisG01

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Yes "Hypoid" just refers to the shape of the gears

IMHO, with the exception of some very old motors that used ATF.... ITS JUST GEAR OIL. All of the "Lower unit" oils will meet or exceed mfg requirements.
He's got a 20 year old motor...he doesn't need $25 oil.

Although, the CEO of Yamaha does need to gas up his Lamborghini....;)
I totally agree that he doesn't need overpriced oil. No question. But if he uses a GL5 oil, it can damage the yellow metal/brass bearings. And some "hypoid" labelled oils can be a GL5 oil. My point is simply to make sure to get the right formulation - not a certain brand. I only mentioned the Merc stuff because there are some definite benefits to it, but it's price isn't all that bad.

I thought he bought a Ferrari for this year?