What additive do marine grade drive lubes like merc and Amsoil Marine have in them that allows them to tolerate some water and still perform that the other gear oils do not?

Thats a very good question- somebody should call Amsoil Tech Support and ask that question. I used to have a contact at Lubrimatic but he is no longer with that company and I have lost track of him.

Where's Hydrocruiser when we need him?

fYI. the previous owner used some kind of synthetic, I changed the oil back to merc HIPerf and I got Jelly. I had to use solvent in the resivours to break it down so I could pour it out. I guess what I am saying is be carefull when switching brands of lubes. I also had an outboard do the same thing when switching to mobile one.

This was provided as an answer to my question on another site. Hardly in layman's terms.

http://en.wikipedia.org/wiki/Surfactant

Bill,
you need an emulsifier ie, metal sulfonates, glycols, ethoxylated phenols, alcohols or acids, fatty soaps.

Ken

snake oil....oil and water don't mix....just B/S

Thanks Ken.

The conclusion I have come to is that the really high end severe duty gear lubes like Amsoil SVG and Redline Shock Proof gear lube that are needed for the drives running more hp/torque than these drives are rated for do not have the water emulsifiers in them so if you choose to run them you had better not get any water in the gear case or your gears will be toast. Real world answer is to change these lubes very very frequently to hopefully catch a water entrance problem as soon as it occurs. Ideally would be changing it after every run like race oil. I wish Amsoil would get off their b*t and add a truely EP gear lube for marine use.

Bill, you are welcome.
I agree with your conclusion.

If you have any water, change it. even if the oil can encapuslate the water molecules.

Ken