I replaced the front bearings and the popping went away. I don't know how they became that worn out with only 39000 on them but they were bad. I replaced them and went on a trip to wyoming. after about 700 miles i was driving on a gravel road and all of a sudden it seemed like something bound up and brought us to a stop. We drove to the nexy town and it was making a grinding noise around the front end or transfer case area. Drove it back home and drove ok but still made lots of noise. I noticed when i got back that the 4 wheel drive didn't want to engage. I don't know if these problems are related but I'm getting tired of repairs on this vehicle with only 39000 on it.