Does The Gear Lube Brand Matter For My Outboard?

kooker

Cadet
Joined
Mar 15, 2015
Messages
6
I'm looking to change my lower unit oil on my mid-90s Tohatsu m40c. I looked at the manual and it stated SAE 80w-90 for the gear lube. Do I NEED to get the Tohatsu brand gear lube or am I okay with a Pennzoil Marine SAE 80w-90 API GL-5 gear lube that can be bought at my local store? I've noticed people saying buy the manufacturer lube but does it really matter?
 

hondam

Petty Officer 1st Class
Joined
Nov 21, 2013
Messages
213
Doesn't matter as long as it's marine gear lube. Although pennzoil is the cheapest or the cheap and I haven't had much luck with it. I would go with the quicksilver if they have that too.
 

muskyfins

Chief Petty Officer
Joined
Jun 7, 2012
Messages
578
In my outboards, I always ran Quicksilver. In my I/O's I usually run Lucas. Never had any issues, but I believe in the addages about new cheap oil being better than old fancy expensive oil. I try to be the hybrid of that and use high quality and keep it clean.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Some swear by Marine Gear Oil, some swear by Car Gear Oil, multigrade 80-90 or 90 fixed grade works pretty same, should be changed every 100-150 worked hours, will depend entirely on each boater. If your lower unit is sealed spot on, that's without any water intrusion at all, car gear oil works fine.

Happy Boating
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,605
I wouldn't be afraid to use any type proper weight oil in my setup. Most every type gear oil you will find specifies that it meets or surpasses manufacturer's specifications. So what is there to worry about. JMHO!
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Has anyone experienced water intrusion at gear box while using Car Gear Oil 80-90 / 90 grade ? Marine Gear Oil has the condition to turn milky if there is water intrusion while Car Gear Oil apparently doesn't.. Is this a Myth or it's a proven fact ?

Been using certified Car Gear Oil 80-90 / 90 since 1996 on all my outboards, but haven't had any water intrusion as to tell, that's why I'm asking. Changing gear lube once a month or around 100 metered worked hours, can't give me the luxury paying for expensive reputed Marine Gear Oil brands which are imported.

Happy Boating
 
Last edited:

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,559
Marine oils may have more anti-corrosion additives, but that's about the only difference. They will all go milky if you get water mixed in.
 
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