The nut that holds the vacuum switch tight against the transfer case appears to have broken off (sheared right in half, as if you were slicing a bagel in half). I guess it happened due to the recent cold snap in Calgary. Anyways, I can't shift into 4wd, and I'm thinking that this is the cause. Is this a nut that I will have to order from Chrysler?
Has this happened to anyone, and if so, how did you fix it? I really need to have 4wd back by tomorrow.

Also, do I need to disassemble the vacuum switch in order to get a new nut on it?

thx in advance for your help

I don't know of the nut you are talking about.

The vacuum switch in the transfer case is more like a large sensor the way it installs. (think of it like a sparkplug the way it screws in)

is your vacuum harness just sitting there loose with half the switch connected to it?

I sure wish I had a digital camera. I'm not 100% sure of the names of all the parts here.

It is sitting there loose (I can remove if from the transfer case with my hand). There is a thin metal piece that protrudes from it and actually enters the transfer case when it is attached (looks like the needle for pumping up a basketball). The nut that holds this thing tight against the transfer case has sheared in half.

I'll try and find a picture of the rear of a transfer case I guess.

http://community.webshots.com/uploads/26306142.jpg?9630

Ok, there is a pic of the rear of an NP231. The red circle is the place where this unit is supposed to attach to. At the moment it is just sitting in it loosely, because the nut that holds it tight into the xfer case is sheared in half. Does this make sense now?