disconnect the plug to the pump, disconnect the air line, and back it up about 12' and see if it unlocks.

There is a logic box in the system when stock. It will run the locker pump when in low range only. Either the logic box or the locker switch is bonky, OR, the engine rebuilder/installer pooched some wiring. I don't know if there is a defeat on the shifter to keep you out of 4hi when locked up, perhaps another function of the logic box, but I believe the tcase shifting is all mechinical.

It's possible some of the tcase gear position switches are misconnected, confusing the logic box.

Last edited by fasteddy; 05/29/12 01:13 AM.
Not responsible for advice not taken...