I have used tractor supply co. house brand ATF and also Brad Penn ATF III-H - with perfect results, shifts very nice, not slippy not too firm, just right.
these are budget ATF too.
to make sure you dont have any leaks - make sure you use some sort of torque wrench to tighten the 6 bolts of the pan, I tightened to 60 inch/lbs and left it there.
The bolts actually dont bottom out, so the 5 or so lb/ft you are applying is just squishing the rubber gasket to seal. If you overtighten it the thing leaks
btw once you install the filter do not unscrew it to adjust. it has a cork type material crush seal that only seals once.
The kickdown solenoid has a bolt through it which has a few O rings and a seal washer too. replace all - about 5 dollars worth of parts. If the casing is cracked and is leaking heavily - replace it. however mine is cracked and still not leaking.