So I want to drain and fill my slow auto tranny on my GT. I did the search function and only found for M/T drain and fills. I just need to know whats the best auto tranny fluid I can use for my car which has 177k. Should I stick to Toyota ATF which I think is Dextron 2 or is there any other better tranny auto tranny fluids that anyone recommends? and how much would I need to fill.

There is a thread about this, I know for sure.
Um, as far as the type of fluid. I run Royal Purple Max ATF....havent looked back since (a bit pricey but I feel its worth it IMO). As far as the volume of fluid needed....
Here, read this....here.

I like Redline ATF fluids. not crazy expensive and run well. I'm sure the royal purple is good also.