Warren Oil still makes 90W mineral oil. Page 38 is the mineral oil. I guess I'm selling it too cheap at $9 a gallon.
http://www.warrenoil.com/catalogs/warren_catalog.pdf Thats all we used in all of our transmissions until synthetic came out. Instead of our transmissions requiring bearings every 100,000 miles, we now go well over a million miles. I use it in everything. Denny got rid of the synthetic because it is so slick that his synchros didn't grab. I don't notice that because I always shift without a clutch anyway.
I sell Warren's Type A ATF for $2.49 a quart. I read in a lot of forums that type A is no longer available. I just got through placing an order for a pallet which is 84 cases of 24.