don't think there was ever a 4 speed auto box.
My '84 T3 with the Subaru engine was an auto.
It had an early trans in that originally, til I blew it up.
Then I put a late Trans in it which has a stronger diff etc. but there was no change in gear ratios from early to late.
What a friend has done with his v6 powered T3 is used the trans from an Audi 100t