I have a 2002 VW Eurovan Weekender w/90,000. A couple of thousand miles back once or twice I noticed a lack of engagement when accelerating suddenly at 35mph. A few hundred miles ago I began to hear a very faint, almost undetectable whining sound that my mechanic insisted was nothing. With a few hundred more miles it became a very noticable whining sound coming from the front. Beginning at the top of a little hill with the engine off and the van in neutral I began a slow roll, the almost crunchy sound begins as soon as the van starts rolling and stops immediately when I apply the breaks. Also, you can hear it at all other cruising speeds. My mechanic put it up in the air and confirmed you can hear the whining/grinding from ten feet away. I am aware of the history of the Eurovan's transmission and have made some calls to experts that say the transmission/transaxle would not make enough noise to hear it in the cabin while driving, that it's got to be wheel bearing/axle/brake related. ?
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.
August, 10, 2011 AT 3:41 PM
Thanks for the diagnostic tip, but you didn't speculate what the problem could be.
August, 10, 2011 AT 10:40 PM
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.
August, 10, 2011 AT 11:26 PM
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?
August, 11, 2011 AT 1:05 AM
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.
July, 7, 2012 AT 1:27 AM
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.