Definitely need to get it in the air high enough to drop everything down and clear of the frame. The support for the rear of the engine needs to be suspended from the frame so you can lift the vehicle without disturbing the support for the rear of the motor. I use a heavy nylon cinch strap under the oil pan and around the frame and cinch it up tight. You can use chain or anything that allows you to support the rear of the engine.
I sure do remember "bench pressing" my share of transmissions! I cannot do that anymore (I could but it would be the last time).