hypoid 90 wt or 80-90 for lower unit

[ddstinman]

need help on using 90 wt or 80-90 wt for my 120 hp, 1999 force , is 80-90 hypoid gear oil ok thanks

 

[Frank Acampora]

Re: hypoid 90 wt or 80-90 for lower unit

Do not use straight 90 weight. 80-90 Hypoid is extreme pressure oil used for auto rear ends. It is acceptable for use in lower units as long as there are no leaks or water intrusion. Marine grade is better since it has more additives to emulsify water and prevent corrosion, but it costs more.