Don't need a slide hammer. Take pump bolts out a ways or put longer ones in, stand trans on bell end and let gravity do the work. Pump comes out pretty easy. Sometimes I tag the tailshaft with a dead blow.

I don't usually even leave the bolts in, I take them out pop the bell on a piece of plywood and let the pump drop totally out. Some guys are sensitive about letting things hit the ground. I don't like to let the pump hit concrete.

Check youtube, plenty of good tear down and build videos for 727's.