Correct Lower Unit Lube - WTF
 

I have a very basic question for you seasoned boat veterans out there. I am replacing the lower unit gear lube on my 1990 292 and I am struggling with all the fricken part numbers out there. The boat has always used Mercury Synthetic SAE90.

Here is what I have found :
Mercury Synthetic SAE90, #92-858064K01
Mercury Quicksilver Mercury High Performance Gear Lube Synthetic QT 92-858064Q01
New Mercury Mercruiser Quicksilver OEM Part #92-8M0078015

Is this just equivalent part#'s between Mercury and Quicksilver ... or is there a technical difference. Any guidance would be GREATLY appreciated!!

if you use the mercruiser 90 92-858064k01 and you look at the back of the quick silver 92-858064Q01 it has the same sticker on the back side as the mercruiser oil..use either one..

as for the 92-8M0078015 i believe that is the new amber color merc hp gear lube,,its soppose to be beter then the olds blue stuff but i have ot used it so i dnt really know..

Thanks for the input!!! So I can basically use any of these three ... they are all synthetic for higher HP engines!