If you jack up the car and place your hands at 12 and 6 oclock and wiggle up and down and left to right is there any play in the wheel if you move it? If there is no play in the wheel it probably would not be ball joints. I know strut bearing can go out and make some funky sounds. Is the sound only when stationary or when you are driving as well?

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Current garage:
'03 4.6is Proud X5 Peasant
'93 Jeep Cherokee (XJ)
'07 Jeep Liberty (KJ)
'88 Jeep Comanche (MJ)