Ok, before I start, I will say that I have looked at the CV axle boots, and they are in good condition, IE not torn. here is the symptoms. When in 4wd ONLY! and under load ONLY! My front left has a popping sound in it, however here is where it gets strange. It is only in 4wd, and it only happens when its under load of some sort. IE taking off, stopping, turning right or left. But when going strait at a constant speed flat ground, no sound nothing even in 4wd. I had someone else drive my jeep as I watched from outside, and I noticed when the pop happens that the front left tire will shutter. Now I have read these forums up down and back again, and a few things I have came up with that might be the problem. A. Front left CV Axle universal is bad. However when on jacks, you can turn the tire, and there is no play at all. B. Intermediate shaft is bad? But that is only for the right side correct? my problem is on the left. C. Bad Front Drive Train. Anyone have an idea what could be the cause, or what I should look for when tearing it apart? Could the intermediate shaft cause problems for the left? Thank you for any replies.