4 Wheel Drive/SUVs: mercury mountaineer front end, ring and pinion gear, mercury mountaineer

Question
i have a1997 mercury mountaineer and their is a clunking sound in the front differental.it sounds likethe old style fords with locking  hubs when you only have one in gaged.

Answer
Dan,

I would try to confirm where the sound is actually coming from.  If it is on the outer end (near the wheel), I would suspect a bad cv, or universal joint.  If the sound is coming from the differential itself, it could be a bad ring and pinion gear, or a broken spider gear.

Carl