I'll help you if you don't know how to search. You can use Dexron 2, 3 or 4. Do NOT use Dexron 5! It has a different formulation that will hurt the seals and do NOT use any other kind of fluid.
I've found Dexron 3 online and that's what I've used.
my '88 uses ATF type A which I'm told is Dexron III,
I tried to buy Walmart Super Tech but all they had was high milage so I bought Valvoline DEX/MERC $21/gallon which works with GM DEXRON-III