As I just recommended to another poster, it could be the stabilizer bar
bushings. They are easy to remove and lubricate. You can do it
yourself.  Look under the truck by the radiator and youll see the
stabilizer bar held in with 2 U-brackets on each side of the frame,
held in with 2 bolts per bracket. Remove the bolts, the bar will drop,
then remove the bushings. They will have a slit in them so you can
remove them from the bar. Put some good water resistant grease on them,
then put them back.
Also I recommend using a 1/2" drive ratchet set to remove the bolts to
give you better torque. A regular 3/8" drive socket will work but with
a lot of effort.

The first thing to look at on the AWD's with "rotational" noises in the front
end is the front driveshaft. They have problems more frequently than the diff,
axles, etc.

I think (but am not sure) that the 96 uses a constant velocity joint on the
transfer case side like my 99.  If so, you cannot rebuild it. Just have to
get a new one - around 225.00.

There is a standard u-joint on the diff side which can be rebuilt, but it is
not usually the  one that fails.  Crunch noises point toward the CV joint.
And it's difficult sometimes to tell if the CV joint is bad without taking
the shaft off.

I's start there!