In general, does oil have a "shelf life" ?
I seem to accumulate quite a few partially used containers of (mostly) gear oil. A Final Drive holds only 8 ounces and a transmission about 24 oz. Usually I just buy another new quart when it comes time to change the FD or Trans but is there any downside to using unused gear oil from a container that was opened 1,2, maybe 3 years ago ?
What about old but never been opened oil ?
What about dino vs synthetic ?
Is engine oil shelf life different from gear oil ?