If your vehicle is showing squeaking or creaking sound when going over speed bumps, here are the most likely causes and the parts you'll need to fix each one.
The sway bar twists inside its rubber bushings when the suspension moves. When these bushings dry out, harden, or wear, they create a classic rubbery squeak over bumps.
Rubber control arm bushings tear or dry rot over time. A very common installation error is tightening the bushing bolts while the vehicle is lifted, causing them to bind and tear immediately when the car's weight is lowered.
Ball joints act as pivot points for the suspension. If their protective boot tears and the grease dries out, they will produce a loud, metallic creak over bumps and often when turning.
The upper mounts connect the struts to the vehicle body. Worn rubber isolators or dry bearings in the mount will creak or squeak as the strut compresses and extends.
Rubber pads sit at the top and bottom of the coil springs to prevent metal-on-metal contact. When these wear through or rot away, the spring rubs against the seat, causing a squeak or creak.
The rubber bushings at the mounting points of the shock absorbers can dry out and squeak. Occasionally, the internal seals of the shock itself will squeak as the rod moves up and down.