SPRING 2015 | MARINE TECHNICIANTODAY
17
TECH TALK
higher viscosity gear oil. Some gear lube manufacturers have started
offering 75W-110 to allow for very heavy loads but not sacrificing
as much fuel efficiency as the 75W-140. Best advice, don’t guess;
contact a lubrication specialist and get the best recommendation
for your application if you are going to use the boat for unusually
heavy loading.
Outdrives will rarely require GL-5 gear lube. When gear lube is specified
it will routinely call for GL-4; these gear lubes contain less extreme
pressure (EP) additives and are suitable for brass alloys. Some outdrives
use brass in clutch components, and the sulfur based EP additives
can react with the brass and destroy these components. Some newer
outdrives are specifying GL-5, so the best policy is to stick with the
recommendations of the outdrive manufacturer. You can also rely on
the lubricant manufacturer’s label to specify the GL ratings, and some
will address brass components.
When selecting gear lubes for your vehicle you will have to choose
between petroleum and synthetic products. There is no argument in
the lubrication profession over this question; synthetics are dominant
in every category that can be measured. In a future article I will go into
depth on comparing petroleum gear lubes to synthetic gear lubes, but
that is beyond the scope of this article.
For questions or comments contact Dan Watson, Certified Lubrication
Specialists STLE, at the following
800-370-2986
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