I'm looking for oil other than the synthetic merc lower unit lube (the blue stuff) and was wondering what I should look for? Many gear oils talk about the API Service GL-4 or GL-5. Does anyone know off hand which one is better for marine outdrive applications? What is best? Have heard some about Redline, Mobil 1, Merc Synthetic, Royal Purple???

I was thinking of trying the Mobil 1 75W-90...anyone use it? With what application/horsepower? Intervals between fluid change?

I use the Amsoil GL-4 in my outdrives as do many others on the board...Fred

Fred,
Which series of the AMSOIL are you running? I notice on their website they have a Series 2000 SAE 75W-90 as well as the Series 2000 SAE 75W-140 and the SAE 75W-90 Synthetic Gear Lube. Which is better the Series 2000 I'm guessing?

Anyone else have success running Mobil One gear lube or anything else?????

Thanks,
Dave

We have bee using the Amsoil series 2000 75/90 in our race boat for the past 4 years, and so far we have not had any drive problems.


Warren
High Priority Offshore

anyone else have suggestions?

I use Pennzoil Marine 100% Synthetic GL-5 in my Bravo I. It works great.

Mr.Gadgets did a test with a drive lube thermometer. In his 28' Checkmate and single Bravo One drive he tested the Merc Hi-Perf (green) synthetic drive lube vs. Royal Purple.

Highest temps @WOT, no drive shower---RESULTS:

Merc Hi-Perf green drive lube: 195*

Royal Purple drive lube: 180*

Of course it would be interesting to see how any other lubes stack up in a test like this.

just bought a case at 5.40 a quart. had good luck sofar.

same here believe it or not Walmart stocks this stuff
priced right too

I looked at my bottle of Amsoil today and it says GL2 through GL5