I have a gearbox that says to use ISO 220 gear oil or equivalent. I cannot find any oil in my area that says ISO 220. I understand that it's basically 90 weight oil. Can I just use a 75-90 synthetic? Please school me on this.
ISO 220 is an industrial gear oil whose [email protected]
*C is defined at 220 cSt +/- 10 % , i.e 198 - 242 cSt .
It's north american counterpart is AGMA 5 R&O gear oil , and alternatively AGMA 5EP Extreme Pressure gear oil .
Most modern automotive SAE 90 gear oil miss the [email protected]
*C by a small margin though close , you need its equivalent in automotive SAE 110 gear oil which isn't available in almost all markets .
No, you can't use automotive SAE 75W90 whose [email protected]
*C is typically 100 - 105 cSt , i.e equivalent to ISO 100 industrial gear oil and it is 2 viscosity grades thinner than that of ISO 220 .
Edit:If you must consider an automotive gear oil due to availability and price issue , please consider a 85W140 with a [email protected]
*C closer to 242 cSt .