get a small pallet and bolt the tranny to it. Use plywood to make some side walls with 2x4 corners. Screw/nail it together and Call Highway Freight at (800) 363-9621

http://www.highwayfreight.com/

They have cheap shipping prices and you can drop it off at the terminal in Atl. Buyer just has to pick it up at a business or the terminal closest to him.