In its reincarnation, it has been to Donnelly Wash and did very well in 2 wheel and 4 wheel.
The donor RAM 1500 had a vacuum disconnect front axle and, of course, the FSJ does not. What saved me is the RAM User Manual instructions to shift Tcase.
Stop in Drive or Reverse, Keep your foot on the brake, turn engine off. At that point T case shifts easily. In the position desired, restart the engine and drive! Works great w/o leaving the car.