"Marine" Gear Oil vs. Regular Gear Oil?

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Is it critical to use gear oil designated as marine gear lube instead of using gear lube that has no such designation? I am indeed puzzled and inquiring minds want to know. Thanks in advance. Hot Ajax
 
The main difference between them should be their interaction with moisture/water. A marine gear oil should be designed to handle water contamination quite well with little or no effect on overall performance for at least a short time. A general automotive gear oil will nto likely have those same characteristics.

The general performance will not likely be all that different, but that water handling ability of a marine gear oil can certainly be crucial in the right conditions.
 
Originally Posted By: MotoTribologist
The main difference between them should be their interaction with moisture/water. A marine gear oil should be designed to handle water contamination quite well with little or no effect on overall performance for at least a short time. A general automotive gear oil will nto likely have those same characteristics.

The general performance will not likely be all that different, but that water handling ability of a marine gear oil can certainly be crucial in the right conditions.


Thanks, MotoTribologist. Good explanation. Much appreciated. Exactly the type of explanation I was looking for, not whether I can save 25 Cents at Walmart
 
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I have seen “milky” marine gear oil in the past, Pennzoil, Evinrude, etc … but my last drain started with very clean water (maybe 4 Oz) followed by very clean oil. This oil was Merc. Gear Lube+
So did it “resist” invasion or what?
 
If your lower unit doesn't take in water, the Pennzoil Marine gear lube is fine. It's easier to get in there with that tapered spout.
 
Originally Posted By: MotoTribologist
The main difference between them should be their interaction with moisture/water. A marine gear oil should be designed to handle water contamination quite well with little or no effect on overall performance for at least a short time. A general automotive gear oil will nto likely have those same characteristics.

The general performance will not likely be all that different, but that water handling ability of a marine gear oil can certainly be crucial in the right conditions.

https://www.amsoil.com/shop/by-product/gear-lube/universal-synthetic-marine-gear-lube/?code=AGMTB-EA
True marine gear performance. Provides superior protection from shock loading. Resists foam and retains extreme-pressure qualities even when subjected to 10% water contamination. For use in outboard lower units, sterndrives, V-drives, bow and tunnel thrusters and marine transmissions Excellent for use in ATVs.
 
FWIW I used Amsoil gear oil in my lower unit one season and it came out black. I went back to Mercury oil (the blue stuff) and never had another problem.
 
Originally Posted By: Silverado12
FWIW I used Amsoil gear oil in my lower unit one season and it came out black. I went back to Mercury oil (the blue stuff) and never had another problem.


What do you think caused the oil to turn black? I have no clue myself, but could it be it was dirty in there due to the Merc oil and the Amsoil just cleaned it up or do you think it was an inferior product?

I have used Amsoil in my old ATV, but that's about as far as it goes today with it's use, other than using their grease for my snowmobiles.
 
Originally Posted By: doyall
What different constituents would be used in a gear oil designed to handle water contamination?

Emulsifiers for the most part.
 
Most consumer grade products wouldn't be anything special. Stern tube lubes are historically very basic, cost wins. There is a movement towards biodegradable lubes more than water tolerant ones. Water tolerance may sound like a good idea to the enthusiast however it's rarely a feature.
 
4WD- Just my opinion but you should check your seals or drain plug gaskets if you are seeing any water in the lower unit drain before any refill.
 
As already said,
marine gear oil has special additives to limit damage if water enters the lower unit.
The question is how long will this work or be useful.
Most boaters change LU oil once a year; fresh in spring and then new fresh in next spring.
If water should enter the LU and you have it in for one year the damage will be most likely
similiar with or without marine grade gear oil. However, difficult to predict!
I have seen hundreds of outboards with automotive gear oil and i never saw a failure because of the oil.
The only failure i saw is a worn Dog on high hour outboards or outboards with a lot of gear shifts.
I use synthetic automotive gear oil for my boats, but i change it at least every 2 months.

However, if you trailer your boat it may be a good idea to check the oil every then and now for water intrusion.

Chris
 
Originally Posted By: supercity
Most consumer grade products wouldn't be anything special. Stern tube lubes are historically very basic, cost wins. There is a movement towards biodegradable lubes more than water tolerant ones. Water tolerance may sound like a good idea to the enthusiast however it's rarely a feature.



I totally disagree.
Mercury Marine markets their oil as being "tacky" this stuff really is, it attaches itself to everything and if water intrusion into the lower unit, it will still protect the gears as best as possible.

I myself, ONE time in my life got cheap and bought Pennzoil Marine Gear Lube. I knew when I was putting it into the lower unit that it was not the same, felt like water compared to the Quicksilver and was easy to wash off my hands. I changed it out in less then a week or two and back to Quicksilver because I couldnt get it out of my mind.

All one has to do is buy a quart of Quicksilver Gear Lube and 1 quart of any other gear lube, your choice. automotive or marine to do the following test.
Here is the test:
1. Open Quicksilver Gear Lube and Open other Gear Lube.
2. Have someone pour a little bit of each gear lube on your two different hands.
3. Go to sink, try to wash off both types of gear lubes from your two hands.
4. Post which gear lube washed off your hands and which one will not!

Without question, Mercury Marine Gear Lube has a tackiness to it unlike anything I have ever experienced. Its really cool and its more then just words that it is designed to protect the lower unit in the event of water intrusion. I know for sure it will do that better then others, IF you get water in your outdrive, if not, then anything will work I guess.
 
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I've done lots of research on this and decided tha t based on my volvo sx drive's requirements that the only thing I will use is volvo penta 75w-90 full synthetic gear oil. It's expensive at 25 dollars a quart but I'd rather spend the 75 dollars a year to sleep well at night. Engine oil for the same boat isn't as crucial in my opinion and am currently running chevron delo 15w-40 until I run out and then will be running Rotella T6.
 
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