Gear oil:Marine vs. automotive

[Oatsmandave]

I was wondering if I could use automotive gear oil (80/90w)in my mercury classic 50 lower unit as I would regular marine lube.I was told (by a marine mechanic,but does he want return business from my blown unit?!?!))that all gear oil is basically the same whether it is marine or car lube cuz all gear oil has to have a anti foaming agent in it since gears spin so fast in a car also.I don't want to ruin my gear case,please help!!! Thanks to all who respond,Dave

 

[Laddies]

Re: Gear oil:Marine vs. automotive

Even though most marine gear lube are rated GL-5, most have other additives added for more protection

 

[LubeDude]

Re: Gear oil:Marine vs. automotive

From the studies that I have done in the past, (Dont ask for references), I have found that regular automotive gear lubes dont have the amount of antifoaming additives that Marine gear lubes have, also they dont deal with moisture like marine gear lubes do. However, using an automotive synthetic gear lube will be fine because the synthetic base stocks handle foaming and moisture better than conventional oils do.<br /><br />The reason for extra anti foaming additives is because the gear cases are so small and the amount of oil is so small that the lube can quickly become just a bunch of bubbles.<br /><br />Now with that said, one would think that the newer standard car lubes of today are probably far superior to the marine gear lubes of the past. But, with the small amount that the lower unit holds, why not just buy the right product and not worry about it.

 

[Texasmark]

Re: Gear oil:Marine vs. automotive

Ok lube, agree.<br /><br />I have used "hypoid" lower unit grease for 50 years.....definitely not GL-1 thru 5 that you put in your tractor or truck and all. Used OMC when I had them and Merc when I had them (all my recent engines) till now.<br /><br />So lo and behold I'm in WW and looking at the Pennzoil Marine products I mentioned (to you here awhile back) and here is 100% Syn GL-5 (like you use in the veh I mentioned) and Penny says it exceeds all (listed them) mftr's warranty req. So I put some in mine and have run some pretty good runs, and it hasn't blown up yet.<br /><br />So I agree.<br /><br />Mark

 

[LubeDude]

Re: Gear oil:Marine vs. automotive

Honestly, I havnt used a marine gear lube in the last three boats I have owned. I buy Amsoil Synthetic gear lube buy the gallon. They now have a apecial marine gear lube, but I still use the automotive stuff.

 

[Oatsmandave]

Re: Gear oil:Marine vs. automotive

Thanks for all your help.I do like the Amsoil idea since I use to use it when I was an Amsoil dealer(small time)here in Minneapolis.I think I'll go to Fleet Farm and pick some up.