Which gearcase lubricants?

[bullheadguide]

Can I use my mercury premium gercase lubricant in all my outboards' lower units, including my yamaha t-8 or is a lubricant horse power or brand specific?

[John in Mn]

I run the Merc Premium in all my motors, no problem. T-8 included.

[rebs]

I use to use mercury in both but I am switching to Pennzoil gear lube

[perchjerker]

thing is about this is anyone can say yea, I use xyz brand oil and have no problems.

But thats easy to say. You arent going to put an oil in your motor then all of the sudden have problems. It could take years for an issue to show up.

you dont really know unless you have tested the oil in a lab environment. I work in a test lab and test gear oil ( I work at a place that makes drive components for autos in the test lab, so we test every aspect of this, not just the oil)

I dont have any recommendations on oil, this is just a comment on this subject

[yamaha dude]

use evenrude lower gear case oil has graphite in the oil works great was told to use by techs at outboard dealer in town checked with other techs was told that this is great stuff to use i use it in my Yamaha motors for a couple of years know

[rebs]

alot of times when people talk about brands of oil, lubes etc it seems it boils down to personal preference. I am thinking its a use what works for you deal.
I guess if a brand is working for you then stay with it. there are differences but how big is the difference ? is any one name brand that much better than another name brand ? with technology today I doubt it. I know there is a post that talks about testing, but when all the testing is done, how much difference is there ? is it enough to wory about ?
just my thoughts, no bashing of any product

[fisher-1]

Local Yamaha dealer has been selling me Mercury Premium Gear lube for my Yamaha 9.9 kicker, according to him its better then Yamalube gear oil,
the manual calls for Hypoid 90 gear lube, I suppose its the same for T8.