Find a flat paved area where you can drive in a complete circle. Drive in a circle a few times one direction then in a circle to the other fairly slow with the window down. If you hear a clicking coming from the front end on one side or the other it is either one CV joint gone bad or both. If the rubber boot is torn then grease will have been thrown all over the inside of the wheel, brake, & shock mount. You can visually check by looking at the inside of the wheel and turning the wheel to left, inspect both sides, then right, inspect both sides. It is hard to inspect without a lift or jacking up the front end. On the wife's X5 both CV joints were replaced, one at 65K the other at 78K. It steers hard at slow speeds but over 10 mph it is fine and instills confidence at higher speeds.