2002 Mercury Mountaineer popping while turning

I'm experiencing suspension thumping and popping sounds whenever I make sharp turns in my Mountaineer, as well as whenever the vehicle is parked on inclined terrain. This makes parallel parking virtually impossible and diminishes the car's ability to make u-turns. The front driver side tire is becoming worn due to this problem. I suspect the possibility of a ball joint or tie-joint failure. I contacted the local dealership for help and they agreed but when I spoke with another mechanic, they suggested cv joint. Help