Was the mechanic able to replicate the noise in the shop? Suspension and alignment specialists are good at finding worn parts through visual inspections, but noises can be elusive, especially if they only occur during a test-drive.
There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.
I'd pay particular attention to the lower control arm bushings and anti-sway bar bushings. Lower load-carrying ball joints can make a squawking noise too even though there is no movement in them during a visual inspection. Also, to check load-carrying ball joints, the car has to be raised up off the wheels. That will eliminate the tension on them and that can stop them from making noise.
Monday, April 20th, 2015 AT 12:17 AM