Unbolt the 4 or so bolts, take the plate off and fish out whats left with a screwdriver and a magnetic pickup tool. Couldnt have gone far. buy new one.
heh all ive got to say is good luck. there isnt much of anything in the back half of the case, but the shifter assembly is up near the top and off to the left. have fun and do waht yjdave said, thats prolly your best option
It's easiest to remove the shifter boot to see what you're doing. Then it's an easy deal to unbolt the 4bolts holding the shift tower on and replace what's needed.
If you're familiar with it, you can change it out from under the jeep. Helps to have a body lift
Just make sure you get all the little pieces out (unless it was just a clean break...then there won't be little pieces). Any little pieces of metal in there will destroy the gears in the transmission and/or t-case.
as bounty said, doing it from below will save you from tearing things apart inside to do it from above... if you want to lower your skid plate, you can let the transmission down as well which will help you