Those above nailed it, esp Darter6.
Did you happen to check the level before you drained/dropped the pan? Even if you didn’t, how ever many quarts you got out should be a good starting point. Filter doesn’t hold a lot like an oil filter.
But it does hold back quite a bit. I start with 4 quarts if I don't/can't drain the converter. Check hot, level, in neutral. Block the wheels so you don't get ran over.
