If you have an old input shaft, stick it in the transmission, zip tie it in place, and don't drain it. If you're not strong enough to bench press it out, make sure you get a jack under it, or have a friend help you. I had one come out unexpectedly once, dropped it on my chest, and ended up with severe costochondritis that required steroids to heal up. No fun.
What are you dropping the trans for?
Paul.