I've been getting this poping from my front axle when changing direction (from forward to reverse, reverse to forward) for better than a year now. I have a lock rite locker in the rear and thought it could be attributed to the back lash but I've driven with the front axle only and the sound is still there. I don't think it's the ring and pinion beacause the sound happens always (ruling out a chiped tooth). I don't think it is the CV joints becasue they appear to be tight (and I had them appart to replace boots). I suspect the entire axle housing is rotating and causing the noise (kind of like axle wrap) because when I look at the diff after being in 4WD I notice the rubber bushings on the two rear supporting bolts are clean on their ends (from having been contacted). What do you think??? I don't know what could be done to correct this.
Tyler

You might check the tightness of the bolts holding the front axle in place. There is one big one in front that attaches it to the front crossmember. See if its loose or if the bracket on the crossmember is damaged, I've seen a few of those break. But if its making noise in 2WD w/ hubs unlocked, then its likely something else, since the front axle and drivetrain would not be moving. Perhaps motor or tranny mounts are loose?

Sounds like something is moving around.. I'm thinking loose or broken front diff mounting. Any chance you could post a pic?

Frank.