I got a 2002 Mountaineer AWD 4.0 V6 with 146k that a loud popping/snapping noise when turning more then 1/2. It will also pop when first starting out but it dosent pop as loud and will only do it sometimes. It is one loud pop when i turn and one quiter pop starting out sometimes. The sound comes from the driver side front. Today i replaced the upper control arm/ball joint (thought this was the main problem making the noise because it was so bad). I have heard various things on what it is, i have heard the cause was from running a spare tire that was a 1" higher then the rest for 2 weeks (brand new tire well other were at 20 percent tread). I have heard that its the CV joint but the boots arent torn... If anybody has any input it would be greatly appreciated! I have been trying to find a answer for the past month and have gotten a good answer!