GL-5 no no

[19Fordy]

Many outboard stern drive marine engines use GL-4 gear oil in their lower unit. It's suppose to be changed every season due to the harsh underwater environment. But, cars wouldn't have the problem.
I wonder if it would be ok for our old Fords. It does not attack yellow metals.
Any thoughts?
http://www.amsoil.com/shop/by-product/gear-lube/universal-synthetic-marine-gear-lube/

 

[jimvette59]

I think it's the non foaming properties that matters in both outboard motors and transmissions. JMHO

 

[50fordcoupeman]

I change the lower unit oil in my Volvo-Penta every season regardless of hours. Manual says to use "30wt engine oil". But in my avatar synchro ****** I use GL-4. If there is ANY question, why take the chance with GL-5? It certainly isn't cost..........