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.
There is a newer version of this tool that has four wireless microphones and two with wires. If you can find that one, use one of the velcro straps to tie two of them to the front of the drive shaft. Place them across from each other so it stays in balance.
Look for anything that fell down and is rubbing on the drive shaft. I've even had tree branches get caught up in there and snap against the balancing weights.
Use some type of metal to insulate one microphone and wire it around the exhaust pipe. Those pipes have been known to cause pinging noises when they heat up and cool down but you typically won't hear that while driving.
Friday, June 1st, 2012 AT 7:04 PM