If you can hear the noise on a hoist, the problem is half diagnosed already. You should be able to locate the source with a stethoscope. If you need higher speeds or weight on the tires to hear it better, there is a tool called a "Chassis Ear" that will help. It consists of six microphones, a switch box, and head phones. You clip the microphones to suspect parts, then listen while on a test drive. Be aware that many mechanics have never seen or heard of this tool but most new car dealers have them. You might be able to find them at some auto parts stores that borrow or rent tools.

Answered by caradiodoc (expert)
17,652 answers provided

Thanks for the diagnostic tip, but you didn't speculate what the problem could be.

Response from john sahakian
1 question asked

Speculating is not diagnosing and almost always leads people to the wrong things. There isn't much that can make noise while moving with the engine off. Rusty brake rotors, worn brake pads, and noisy wheel bearings are the most common causes of noise. Noisy wheel bearings will sound like an airplane engine buzzing.

Answered by caradiodoc (expert)
17,652 answers provided

If I'm hearing you correctly, rolling down a hill with everything off and still hearing the noise means it has nothing to do with the transmission? For the transaxle to make noise the car would have to be on and driving?

Response from john sahakian
1 question asked

Noisy wheel bearings are common. In 16 years of doing suspension and alignment repairs, I've never heard a noisy bearing in a transmission. Since you can hear the noise on a hoist, listen next to both wheel bearings with a stethoscope.

Answered by caradiodoc (expert)
17,652 answers provided

try loading the bearing. steer left and then back right. which way you turn to quiet it, it;s the opposite side if it's a wheel bearing. if it gets bad enough it might cause an abs light....

Answered by vwscott
0 questions asked