Have you found the source of your popping sound?? Check this ...
Jack up that wheel, and turn your steering wheel all the way to full bump. Then while looking at your axle u-joint, spin the tire, and see if your u-joint is good. I had one that was toast, but seemed tight when we checked it on the trail. It was popping and clicking when in 4-low, and when turning on the roads in 2wd. If there is any play in it change it out before it goes completely and wrecks your axle.