They dont make em like they used to. Literally! These jeeps are all centrally controlled by modules that have to be programmed individually at the dealer.
But i would say get a donor, same year same engine that runs. Swap everything from the transmission and transfer case, all wiring and you would be on the right track. You might have better luck making your 2x4 a 4x4 with a part time transfer case from a liberty and the front 4x4 parts from a wrecked wk with the same gears as your wk.
You will end up with a truggy jeep wk that MIGHT work but will have issues.
Buy a 4x4 or start the project and just dig in. Trolling these forums with questions like yours will get you nowhere.
2008 Laredo X 4.7 with 245/70-17 AT2 RC lift
2013 Hemi Durango Crew