If there is too much fluid it CAN foam up and spill out of the tranny dipstick...if the tranny gets too hot...depending on how much too much. Not really a great idea to figure it'll spill out if you put too much in.
The AW4 takes about 8-9 quarts of Dex III or better. If you are just draining and refilling it takes 3.5 quarts...the Torque Converter, tranny lines, pump etc. is holding the rest.
You need to check the fluid on a level slab, like a gas station, after the Jeep is up to temp (driving for 20 minutes), in Park (or Neutral) with the engine running.
If you think you have TOO much, drain the pan and put 3.5 qts. back in.