I just bought this 01 s2000 and it has an odd noise that is really only heard at low speeds and only starts after the car has been driving for about 10 minutes. I do not hear it at normal driving speeds. The car has 186,000 miles on it. I just changed the diff fluid and the fluid that was in there looked pretty good. It was still fairly clear, just a bit golden brown. There were some shavings on the drain plug. Is this amount of shavings normal for a car with this mileage?





I raised the car up and felt for wheel movement and it is rock solid. Do the wheel bearings on these go bad without movement? I've always seen movement in the hub with bad wheel bearings before. I also torqued the axle nut with a 3ft. breaker bar as hard as I could and got a tiny bit more turn on the nut but its still making the noise after tightening it. Here is the video of the noise. Any ideas? Thanks.

right rear noise

 

That does not sound like any diff noise I've heard. As you go faster does the knocking sound get faster?

 

If I go much faster than that, I can't hear it at all. How about those shavings? Is that normal wear and tear for tons of miles?

 

Oil has been changed many times I'm sure the drain plug does look normal it's just paste.

 

I would start looking for something under the car interfering, touching, the rotating assembly. I would have a good look under the car while on a lift to find where the sound is coming from. It could be something as simple as a loose cable or something like that.

 

^^^ yep that's the easiest thing to do first. Sounds like something interfering. Worse case scenario you have a missing tooth out of the ring or pinion gear, or a chewed up half shaft prop bearing or and cup. Do you "feel" that sound at all like a notch or pulse in your seat? Or is it purely audio? Try and key in on that if you can.

 

It is purely audio. I looked underneath and saw nothing hitting, although I did not do that while the wheel was moving and car running.

 

If a tooth was broke off the ring or pinion he would have sound all the time and it would get louder as he drove. I would look for something loose or foreign underneath the car, good luck

 

So it doesn't sound like the diff to me and you guys agree?

What about wheel bearing? Ever seen one make noise but not have any play?

 

Okay, so I got it up on a lift today and checked everything out. Only thing that was found was that the caliper had movement when pushing on it. The guide pins had movement when wiggled. We think that the brake is binding up and causing that clunk. Im going to replace the caliper and guide pins and I'll update. Thanks guys.