If you're sensitive to the noises of your car it is likely that you'll catch something like a dry or failing bearing before it is so bad that you'd feel play or hear the louder noises that indicate a definite failure.

Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

On my Opel/Holden Astra H (150KKm, front wheel drive, m32 6-speed manual transmission) I hear a slight grinding noise from the right-front, starting at about 40 km/h. The noise is synchronous to the vehicle speed, independent of engine rpm. It remains the same if I press the clutch, change the gear or switch to neutral. It also does not change if I make turns. The best description of the noise would be the sound of a steel brush pressed against a turning shaft. What i am not sure: There is a possibility that the sound would be more silent while accelerating.

Since it is a moving noise and happens at a relatively high speed it will probably be a very faint sound when the car is on blocks (and may not occur at all if it requires a loaded suspension). So use the "screwdriver trick" (a video if you prefer) or a stethoscope to help you isolate the sound.

The diagnosis that you're done pretty much narrows it down to something between the output of the transmission and the wheels, including the brakes. You can eliminate the brakes, by lightly applying the brake while listening for the noise to go away (it is the brake) or not (something else) – while driving.

So the possibilities would be: The differential in the gearbox, the intermediate shaft bearing, the CV joints of the axle, the wheel bearing or a slightly seized brake.

I tend to exclude the wheel bearing: Because the noise remains the same when making turns and the wheel bearing has no feel-able play when I jacked up the car and shacked the wheel.

Another think you could try is to have somebody drive the car by you as you listen on a quite stretch of road. It may be easier to hear and isolate from the outside.

What I'd suggest is that you lift and block up the car and pull the front wheel(s) and inspect carefully. Some things to look for: