I know alot of guys have switched from the Merc Hi Perf gear lube to synthetic 75-90 ..

Is automotive Synthetic 75-90 GL-5 good for the Bravos?any issues?
Im thinking been Synthetic will be better than the merc lube..

Be careful... it isn't just about changing to a synthetic...

You need to choose something that also has additives in it that can handle high levels of moisture. Most automotive lubes do not. Make sure it says "marine use" on it. If it does not well then get ready for drive issues down the road.

well the reason I ask is I read alot of people using Mobil 1..thats a automotive gear lube..

thanks..maybe Il see you at the river shiver.

IMO, this is the best!!
http://www.amsoil.com/storefront/agm.aspx

Thanks..

But right now Im not looking for brand,,Im wondering if Automotive Synthetic 75-90 GL-5 is ok to use in a Bravo..

I think alot of guys on here use it..any issues?

I have used it since I bought my Mariah in 1995. This was with the stock 350 mag for 10 years to my current 350HP Vortec motor for the last 6 years. I have not had one issue with my Alpha One.

There's is nothing wrong with using a, as you say it, an automotive gear oil. A GL-5, however, does have more sulphur in it, an extreme pressure additive, but sulphur can have an adverse effect on soft yellow metals if it gets too hot, which are sometimes found in marine lower units. Also, a regular gear oil will not have a water emulsifier built into, such as the above mentioned AMSOIL Marine Gear Oil does. That product is able to handle 10% water pollution, without having an effect on it.

I switch every bravo I have to royal purple..I consider merc lube trash...after a few years sitting the stuff turns to sludge in the bottle and the in res in the boat....some have had that clog, destroy the drive as looks like you are fine !!! no issues switching...

I spent alot of time and thousands testing outdrive lower gears trying to get them to live longer, experimented with heat treating, cry/iso rem, dlc coating, back lash, you name it. I used Royal purple the whole time convinced it was great stuff, when I finally started using something BETTER I doubled the life of my gears over everything else I ever tried, I NOW consider Royal purple gear oil garbage and would never run it in a Bravo again behind BIG power. FWIW based on my personal experience, Smitty
I now use NEO from the bravo shop (haven't ran it long enough to form a opinion) and I did have good gear life with Amsoil Severe gear with 10-20% lucas oil stabilizer

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