well...lets start another thread !!

Uh, no; it would turn into this

So why do the tell you not to mix it with non- synthetic gear lubes. They always said to let a drive drain overnight to get all of old lube out before filling with hi perf gear lube. I just figured that meant it was full synthetic.

As important the gear lube is, the use of the drive shower is just as important! I know you all know this but just wanted to remind.

Thanks Guys..

Now back to the original question

its better not to mix different brands of oil...they each have their own additives,compounds and a lot of times those additives do not play well with others,or are not compatible at all,and results in a kind of sludge that wont do anything good for your engine/outdrive...also if you let it drain overnight,you know the used oil is completely out...i spray some brake cleaner in my bravo,and i can see some more ch**t coming out

Absolutely you can use an automotive 75W90 synthetic gear lube. As long as you never have a seal go bad and get water in the gear case you will be fine. Speaking of water in the gear case, I was out on the river a few years back with a buddy of mine and we popped the hatch to check something out. I noticed his gear lube bottle looked like it had carmel milkshake in it. I asked how long it had been that way and he said for about 10 hours. We had to run another couple hours that day to get back to the ramp. When we got home I drained the gear lube and it was pure milkshake. I had been doing all of this guy's maintenance for him and we were running Amsoil 80W90 Marine Gear Lube at the time. We pulled the drive and took it to a Merc certified buddy of mine that worked at a local dealership. He tore the drive down, inspected all the gears and bearings, replaced al the seals and declared the drive to be in excellent condition (I think it had about 850 hours on it at the time). Not sure the outcome would have been the same with an automotive gear lube that is not designed to emulsify a certain percentage of water.

Thanks..

all automotive synthetic lubes I looked at have some muisture protection,,do marine lubes have something else in them?


http://www.synthetic-oil-tech.com/Ge...te%20Paper.pdf

I work for a company that makes oil additives, including the emulsifiers. A couple of years ago, I asked our head chemist that same question - I can't remember verbatim, but his response was along these lines - "no, they all have an emulsifier in them, but the marine ones have more of it, and typically more anti-corrosion additives as well."

Will they withstand up to 10% contamination?

Universal Synthetic Marine Gear Lube SAE 75W/80W-90 (AGM)
High Performance lubricant engineered to meet the demands of marine applications. AMSOIL Universal Synthetic Marine Gear Lube provides:

•Excellent Gear and Bearing Protection even when contaminated with 10% water
•Reduced Friction and Wear
•Rust and Corrosion Protection
•Long Seal Life
•Superior Foam Prevention