I have a '99 Grand Cherokee with Select-Trac with Vari-lock. On my shift console I have 2wd, 4wd part time, 4wd full time, N, and 4wd low. The previous owner I bought it from had the front end replaced because he quote "burned it up". He really couldn't expand on it much more than that other to say it started making a lot of noise and he had a reputable local shop replace the entire front end.
When test driving it, I noticed a clicking sound that made me think the cv joints were going out. It only occurs on sharp right hand turns, not on left turns at all. Used it as a point to talk him down a bit, so I bought it.
Thinking it was a cv joint going out, this is what it sounds like, I replaced the half shafts last week only to find out the clicking was still there. It is not as pronounced as previous and it takes a tighter turn to produce than before. Drove up some paved switch backs locally. Clicking only occurs on sharp right hand turns, while acellerating, going up hill. It does not occur on left hand turns. It does not occur on sharp right hand turns going down hill with no throttle. I can make the noise on sharp right hand figure 8s on flat pavement, which also has some throttle engagement.
I have noticed the steering feels like its in 4wd despite the shift selector being in 2wd. Putting the front end in the air in 4wd part time, and spinning one wheel causes the other to spin the opposite direction. The driveshaft does not turn. However, after about 3/4 of a revolution of either right or left tire, there is a small click and then the tire becomes increasingly more difficult to turn into it almost lock ups. This is what I would interpret a Vari-lock axle to do simply by virtue of its name. I cannot spin either tire manually to duplicate the clicking I'm hearing.
I'm not positive its an axle problem, but it is occurring at or forward of the driver's seat area.
I've also noticed a audible hum at speeds over 40. The noise does not increase in volume with speed after that, but is not noticeable at speeds under 40.
Thoughts on if this is an axle problem, transfer case problem, or something else?