if you get fittings to fit off the trans lines off the rad you can use two buckets, one to catch the fluid coming out, the other filled with new fluid and suck the fluid up with the other line. idle the engine till you got red fluid coming out the draining hose. use clear hose too. im sure theres a vid on yt to follow along.
then again, if your fluid is black, that trans might be on its last legs, if its acting up a fluid swaps not gonna fix it, actually might kill it the rest of the way.