I'm doing a gear swap in my 05 Jeep Liberty and it calls for 75w90 synthetic in the rear. I have had two quarts of Redline on the shelf for years, in fact the sticker on it says 2002.

The caps have never been removed, so they have been sealed all these years. Should I worry about pouring this stuff in a new gear set and Detroit Tru-trac?

I'd use it.

Use it, from what i read, as it gets older it goes to the higher viscosity, reg oil the opposite. Not sure what synthetic oils eventually brake down to but reg. oil remains oil indefinitely just gets dirty and the additives deteriorate. Feel free to correct me if I'm wrong, just what i read.

To be safe, I'd call Redline and see what they recommend for shelf-life. While you have then on the phone, maybe confirm your application as well.

Generally it's the additives falling out of suspension is the concern.

No need to change synthetic in a vehicle after that amount of time so why would being in a clean sealed container bother it? use it. Or send it to me, I'll use it.
Doug

Or me.
R.

I'm pretty sure most of what it is made out of is north of a million years old already.

Kevin

"Would you trust old synthetic gear oil"? in a heartbeat