Dexron or Mercon III or one that is compatible with those two types. Power Steering takes Type F Transmission Fluid.
Mercon
Dex\Merc
The Ford Bronco transmission can use any SAE certified transmission fluid. Ford transmissions manufactured before 1979 will need an F type transmission fluid.
I'd suggest using a Dextron III/Mercon automatic transmission fluid.
It all depends on the type of transmission the truck has, if it is manual than manual transmission fluid is used where if it is automatic, automatic transmission fluid is used Not always, my 91 302 with a 5 speed manual uses auto fluid, a lot of manuals do.
dextron
Type F automatic transmission fluid meets or exceeds all lincoln, ford, and mercury type automatic transmissions regardless of year. Brands are a mercon V or Halvoline.
dextron III
Auto
Dexron 3 is prefered.
Mopar atf+3, 9 quarts
It's an automatic.