You can pull the vacuum hose plug off of the front axle and then with the
engine running see if you can tell if one side still has vacuum
to it.  If it does, then place that side onto the opposite fitting from
where you pulled it off.  That should disengage it and hold it there until
you can check out the entire system.  You didn't tell us what type of
vehicle you have but if it is like mine (91 YJ) then this should work for
you.  My YJ has the switch for the 4WD light on the front axle disconnect so
it would still be lit up if the front axle is still engaged.  Might yours be
like this also?  If so, you have a different problem.

Good luck and Happy New Year!
Dave

I was posting as Jeepers and just realized that someone else posts
here using the same name ( or someone else use to use that name) so
you will notice I changed my nick a bit.

Anyways 2 days ago I had my vehicle in 4WD and today I went to work
and noticed that the front axles are locked in 4wd. The indicator
light does not indicate that I'm in 4WD and responds to me shifting in
and out of 4WD. From what I have read when I shift to 4WD the transfer
case of course shifts the gears and via vacuum it trips a pressure
switch to energize the indicator light.....this all seems to be in
order. Also I understand it also applys or removes vacuum on the axle
shift motor and engages / disengages the front axles.

So from this I guess I can assume one of the following:

1:) I have a bad vacuum line
2:) The shift motor diaphram is damaged
3:) The shift linkage from the shift motor is damaged / jammed

Is there an easy way to manually disengage this until I get time after
NewYears to really look at the problem.

Also does it apply vacuum to engage the front axles or remove vacuum?