So I've been trying to figure out what is going on with the Z for over a month now. It started out relatively quiet, but now it's very loud and happens more often.

The rear axle in the Z is making a rotational metallic noise, almost like something scraping or making contact with something else. It's loud and like I said, rotational, so it changes with speed. It typically happens when I'm either:

1. Decelerating from highway speeds (or really anything above about 40-45 MPH). As soon as I start getting on the brakes and get some force going forwards from deceleration, you can hear it.

2. It just started being noticeable (albeit not quite as loud) at highway speeds above about 55-60 MPH. It's faint but noticeable from inside the cabin.

3. It happens nearly 100% of the time when in reverse, whether I am in gear or coasting in neutral. It is most prominent and loud when I'm reversing at any kind of speed (especially when I'm reversing downhill).

The noise is definitely coming from the rear end somewhere and it happens regardless of what gear I am in, on the brakes and off the brakes both. It has gotten progressively worse over the past few weeks. It's mostly noticeable in town during stop-and-go driving but, like I said, it's very loud and the most easily reproduced while reversing.

I haven't noticed any kind of mechanical effect from the issue but its incredibly annoying and I'm at a loss trying to figure out what it might be.

63,000 miles; and it's a 2003.

 

You must be new lol. It's common on the Z's and attributed to a dirty axle.

You can search and find out how to clean and grease it.

 

It's definitely not the axle click. I've taken care of that already.

This is an entirely different issue.

 

Wheel bearing, brakes could be a lot.


I would take it to a mechanic.

 

Sounds like a wheel bearing. Usually makes more noise when weight transfers to that wheel. Do you notice it happens when you turn? Such as a bad left bearing will make more noise when turning hard right.

I replaced the wheel bearing on my B13 on the front left. It was noisy as hell whenever I turned right or was braking a tad aggressively.

 

Most likely a wheel bearing. Jack it up and check for wobble.

 

I planned on checking the wheel bearings next time I have a day off. It's really random to reproduce going forwards but if I go in reverse, it is a 100% chance that it happens, and it's louder than hell.