If you leave the torque converter attached to the flex plate, you will dump a ton of ATF on the floor when you disconnect the tranny from the engine.

Pull the thin metal inspection cover from the bottom of the bellhousing. Then look for bolts or nuts on the front, not back of the flexplate. All autos I ever did had the bolts sticking thru the flexplate, so they had to be removed from the front, not the back. There will be 4 or 5 of them. Remove the bolts/nuts and then use a large screwdriver to force the converter back away from the flexplate. Now you can remove the tranny and leave the converter in place.