Shop marine gear oil and gear lube for outboard lower units, sterndrives and selected marine gearboxes. Products include manufacturer-branded lubricants, compatible alternatives and service packs where stated.
How to choose marine gear oil
Check the equipment manual for the required viscosity, API classification and manufacturer approval. SAE 90, 80W-90, GL-4 and GL-5 products are not automatically interchangeable, particularly where yellow-metal components or a specific additive package are involved.
- Match the required grade and OEM specification.
- Check the gearbox or lower-unit fill capacity.
- Replace sealing washers and inspect drained oil for water or metal contamination.
Marine gear oil FAQ
Can GL-5 always replace GL-4?
No. Use only the classification approved by the manufacturer, especially in gearboxes containing brass or bronze components.
Why does lower-unit oil look milky?
A milky appearance can indicate water contamination. The seals and pressure integrity of the gearcase should be checked before continued use.
