Time marches on. Products are updated as specs become obsolete. There used to be six gear lube classifications, GL1 through 6. Now only 4 & 5 are currently specified. Case in point, try finding any of those listed in your service manual. Straight 80, 90 or 140 really don't exist anymore as most are multigrades. Also, that Dexron specced hasn't existed in that form since the '70s (probably). So, do the best you can with what's available. :)
