Dexron 3 for 97. Castrol SMX-S for latter models. There should be a sticker on your transmission cas. In case you cant get either, I keep them both in stock.
Haven't been here for a while so thought I'd say hello , also to let you know I use Redline D4ATF in the T56 gearbox of my Corvette. Made it easier to shift the gears during cold winter starts and no problems at speed either.