Using a Floor Jack as a Transmission Jack?

I've done it with a short 2x8 or 12x12 piece of plywood on the larger floor jacks. If you can wrap a ratchet strap over it and the trans to secure it and just place yourself out of harms way. Like Rumblefish said, you run out of room unless the car is way up in the air. with either jacks. I've always had to slid the trans off the jack and out and even then the bell will cause you some grief.

Be sure to plug to wire/zip tie a back of the trans tail shaft as you will get fluid out if tipped down.