Have you had the ball joints replaced recently? The OEM ball joints are sealed, if you had one replaced it may have replaced with a greaseable fitting. The ball joint may look OK but needs to be sprayed with a grease gun. I had this problem and took my car to 5 different mechanics who told me that the car was just old. Finally took it to a dealership where the mechanic said the noise was coming from the tie rod end or ball joint area. It was at that time he noticed that the ball joint had been replaced with a zeck (greasable fitting) that was missing its dust cap. He took a grease gun shot it full of grease and then replaced the dust cap and I haven't had a problem since.