Rhythmic clunking noise from right rear wheel/exle

jchalfant1

I have a 2003 OBW that has developed a clunk, clunk, clunk noise form the right rear wheel area. Seems like it might be an axle (bad cv joint). the noise increases on the highway forcing me to take a secondary road. I am not quite sure how to diagnose a bad rear cv joint as all the boots are untorn. the frequency of the noise seems to match wheel rotation but it isn't a clack, clack , clack like I am used to in a front axle situation. If I have someone drive the car slowly I can bit my hand on the fender and run alongside the car and I can "feel" the clunk like some one is hitting the car with a hammer. I can find nothing loose. Any thoughts and help would be appreciated. Thanks

saedave

I presume you have checked the tire and rim and checked tightness of the wheel lugs.. Exchanging left and right rear wheels temporarily might make sure.

jchalfant1

New tires were just installed due to a one bad belt in a tire so tires are fine. This is a sharper sound more like a hammer hitting a suspension part but there are no loose parts rotating and hitting. After reading posts there is talk of differentials and other parts in a AWD system that I am not all that familiar with. Seems to be emanating from the hub area of the wheel assembly so my thoughts are:

bearing-usually growls not clunks but I am not sure if it could make a sharp clunking noise.
CV joints- usually gets louder when you turn but this is a rear axle so no turning to test. My boots seem fine but joints can still just wear out. Car has 180k miles.
Differential- I know nothing but from what I have read this could cause a clunking noise.
Brake caliper- a quick inspection turns up nothing alarming.

If this is the drive axle how difficult is a rear axle on a OBW to replace. I have done my Honda and VW for years so I know the basics just not the tricks on a Subaru.

Thanks again for your thoughts. Jon

ateixeira

My guess is wheel bearing.

We had a Mazda 626 that had a bearing go out and I described the sound as "chunk chunk chunk", also speed-dependent.

xwesx

I suspect the same thing. When the bearing went out on the rear axle of my old '69 Econoline, it was the same clunking. It didn't turn into a growl until the entire assembly disintegrated!