I'm going to swap my tranny with a rebuilt. Do I drain the fluid before removal?

How about the transfer case. Should I remove it before or after the tranny? I would think it would be easier to do outside the truck if possible.

Okay the tranny is out. Yes drain the fluid and remove the transfer case. The cross member was riding on the torsion bars, so I back them off as well to get the cross member free. The 1 ton trans jack worked awesome. I had to have my son help me with the transfer case as it is pretty heavy to handle alone. I was surprised how small the 4l80e trans is after removal. Nice!