Geo Metro differential/transmission fluid question

I just replaced an axle on my 95 Geo Metro, and lost a fair amount of fluid when the spine was out. This is an automatic transmission, but I simply couldn’t tell if it was transmission fluid that was lost or some weight of oil. I can’t find any reference to any gear oil being used anywhere in the car while searching fluid capacities, so it seems it must be that the transmission fluid lubricates the differential as well. I don’t have any experience with automatics, so of course I want to be absolutely sure there’s no gear oil lubricating anything before I proceed to top off the transmission. Thanks!

“transmission fluid lubricates the differential as well”

That’s the case with every FWD trans I’ve ever seen.

Thanks, I just wanted to be sure…

I had an 81 Plymouth Horizon Automatic that the differential was filled seperatly from the transmission. They were both filled with ATF at the factory for fuel economy reason, but if the differential became noisey, the cure was 85/90 gear oil in the diff. I did this at 80 ooo miles and the diff was still quiet at 140000 when the car was sold.