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
"Marine" Gear Oil vs. Regular Gear Oil?
- Thread starter Hot_Ajax
- Start date
- Status
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.
Since they carry marine gear oil at Walmart and typically you use 1 to 2 QTs, it would seem a no brainier.
Last edited:
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.
Last edited:
Moto nailed it on the head.
Moto sure did. Loved his response.
What different constituents would be used in a gear oil designed to handle water contamination?
4WD
$50 site donor 2023
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?
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.
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.
Originally Posted By: doyall
What different constituents would be used in a gear oil designed to handle water contamination?
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.
It's not hard to take a coolant pressure tester and hillbilly rig it with a marine gear oil pump hose into a drive/lower unit pressure tester.
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.
Last edited:
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.
Last edited:
- Status
