Lower unit oil?

[tmt]

Will Valvoline 75w90 gear oil be ok to put in my lower unit?

 

[lindy46]

Re: Lower unit oil?

You should use marine gear oil as it has additives to emulsify any water that may get in the lower unit.

 

[Tim Frank]

Re: Lower unit oil?

Will Valvoline 75w90 gear oil be ok to put in my lower unit?

No. Use the lube that is recommended in the owner's manual.

 

[virii01]

Re: Lower unit oil?

No. Use the lube that is recommended in the owner's manual.

I picked up some Royal Purple 75-90 gear oil for my lower unit after reading on here that it was ok. Is that not the case, or is synthetic gear oil different?

http://www.royalpurple.com/gear-oil-m.html

 

[Vic.S]

Re: Lower unit oil?

You dont say what motor.
Electric shifts require a special oil. Most others use a high viscosity outboard gear oil around SAE 80W90.
As said the outboard gear oil contains emulsifiers and also additional inhibitors to guard against the effects of water ingress. They are the reasons for using it rather than automotive oils.

 

[virii01]

Re: Lower unit oil?

Mine is a '81 115.

 

[Tim Frank]

Re: Lower unit oil?

I picked up some Royal Purple 75-90 gear oil for my lower unit after reading on here that it was ok. Is that not the case, or is synthetic gear oil different?

http://www.royalpurple.com/gear-oil-m.html

Use the lube that is recommended in the owner's manual.
If you aren't prepared to do that, choose whatever you want...or take whatever suggestion you get in here and run with it.

Personally, I usually defer to the manufacturer and their team of engineers who designed the motor... but that is just me.

 

[Vic.S]

Re: Lower unit oil?

According to the data sheet the Royal purple oil is designed not to emulsify with water.
It does not contain the inhibitors that an outboard gear oil supposedly does.

For those two reasons it would not be a good choice.

I don't understand the reluctance to use the correct oil.

 

[1946Zephyr]

Re: Lower unit oil?

Yea, I agree with these guys here. Use the lubricant that is recemended. Automotive types may save you a few nickles, but the correct thing is designed to work with a hunk of metal that lives under water.