Hi all, I have 3-4 year old unopened royal purple 75w90 and Mobil ATF sitting in my garage from my 91 XJ. I want to change my diffs and transfer case fluid after work but I want to confirm these are 1. not to old, 2. still the correct fluid for my 99'.

I have read mixed reviews on the type but most say unopened bottles shouldn't be a concern unless they are very old.

Cheers

 

From what I read oil doesn't go bad if it's not exposed to the air. You should be ok there if it's been sealed.

 

+1. I wouldn't be really worried about quality synthetics in unopened bottles degrading unless you cooked them or something.