Gear oil

[Bullring]

I need to change the oil in my straw chopper gearbox, the manual states SAE90 gear oil, but most places don’t seem to stock straight 90 anymore, its all SAE 80-90 gear oil, what’s the difference and is it suitable, I presume it’s just the viscosity?

 

[Timbo]

Yes & Yes. 80w-90 is a multigrade.

 

[76masseyman]

Main thing to check is if it’s asking for GL4 or GL5.
I expect it could be 5 if the gearbox is under big pressure. If unsure, go GL5 anyway.
An 80w/90 has a greater temperature range than a mono grade 90, and will be a tad thinner when cold ( not a problem as it will move easier on start up )
You could find the 80w/90 cheaper than 90 as it’s more common.

 

[Bullring]

The manual doesn’t state GL4 or GL5.

 

[ACEngineering]

The manual doesn’t state GL4 or GL5.

GL5 everything