On your front diff on the drivers side is where the cable attaches to engage the diff lock, check to see if it is moving or not when you pull the lever. I just ordered a new cable for mine because it is getting sticky and will engage but won't disengage by itself, I have to use a screw driver to move the lever back to unlock the diff. You may have a damaged and/or seized cable and the cable just won't move, you can use a screw driver or something to move the lever without using the cable to make sure it is the cable and not something inside the diff that has failed. Good luck and let us know what you find, I would be pretty sure that it is the cable because not too much other stuff that will do that to you or atleast I hope it is the cable. :wave: