I went a step further than a stethoscope to find a suspension problem on my car, and bought a Chassis Ear. It has 6 very sensitive clip on microphones plugged into a small 6 channel amplifier hooked up to headphones. You can switch between the microphones with a selector switch. With the microphones hooked up the front suspension I could hear the key turning the ignition switch, starter,every lifter, alternator, and everything else that moves. Figured out that if I started turning down the volume down, I could filter out all of the other noises to hear what was making the loudest noise I was looking for. It's tough to hold a screwdriver to your ear listening for a suspension noise driving down the road.
