Firstly the obvious- don't drive it with the CDL in on any surface with good traction, tarmac etc. If you must move it out the way for instance make small steering angles and feel what's going on.
If it's in High range then it should not be locked, if you have a CDL or similar button, check it is not engaged.
Have you done anything that may have caused wire damage underneath or even cleaned the inside of the car and moved something?
If you have a separate fuse for CDL or diff locks in general, you could try pulling this fuse to see if it disengages. I think the motors are spring return but can't remember for the 80 and not sure on the 100 so perhaps somebody else could confirm. Anyway, if you try the fuse and it disengages and you can feel it as being so then it gets the vehicle mobile again until you can tackle it in better weather. Just make sure you get it sorted before you need it.