Transmission oil expired date

[Yoni159]

I have castrol 80w90 gl5 oil and its days on the bottle 20/8/20 its Date of manufacture but i bought that bottle 1.5 year's ago.. can i still use it or buy new one?

[Tromper]

I doubt it'll be an issue.  Even Mfr's say 5 years.  Chemists say 15 if ya dig around, but the standards update periodically so it won't be the latest greatest  Of course your bike is likely older than the oil that should be an issue since it was built to the older standard.

Google around a bit and see if you're comfortable using it.
If not. Gear oil is cheap, drop the old stuff at the local hazmat for recycling.