Grinding noise at low speed from front of car

[Frostedbutts]

I'm not really sure what else this could be at this point so I am hoping to find someone that can help.

There's a grinding noise coming from the front of the car at low speeds. It seems to get louder the slower I go (whether that's due to engine noise or not I am not positive), but at a really slow roll it doesn't seem to happen. I need to be going about 3-5mph for it to happen.

Things I've tried:
- New front pads
- Wobbled the front wheels, there doesn't seem to be any play.
- Pulled the AWD fuse, no change.

Clutch in/out doesn't matter. Boost doesn't appear to effect it, I can be coasting out of gear and it'll happen or under acceleration it'll happen. You can't hear it from outside the car, and it's a lot louder when the windows are up.

My only other thought would be new rear pads, if the grinding noise is somehow transferring from rear to front but I highly doubt it.

[caliber676]

Noise diagnosis is by far one of the hardest things to try and fix/locate. I would say that you have to start and determine if it is a rotational noise or a sporadic/ stationary noise. If it is a rotational noise it will have a "frequency" per-say or an "on-off" type of noise. (example) Like a rock stuck in a tire it will make a noise, say, 3 times a second (on-off-on-off) going 10km/h constantly. You can seperate rotational noises based on the frequency of the noise by either electrical tools or just common sense. If a noise happens say 5x per second and is speed dependent you would know the only rotating part of the vehicle that would be rotating that slow while moving is the wheels. If its a noise thats occurring while stationary it engine related and will have a high frequency as the engine is moving at 800rpm+. Now if its occurring while moving at a high frequency (engine rpm) then you can assume its within the engine and input side of the transmission. Its just a rough idea of figuring out how to isolate noises, there is actually a science behind it and with certain tools and determining frequency you can locate a noise very efficiently.

Now if a noise is completely sporadic like a blown shock you'd have to replicate the condition and isolate.

Given your description (and you have to confirm your claims), you aren't looking for a wheel/tire/brake noise as all of those would be audible from outside the vehicle. You are looking for something that can resonate into the vehicle while in motion. Without knowing if it has that key frequency noise as opposed to say, a rattle is key in going further. But a number of places to maybe take a look would be wheel bearings (stethoscope on hub while driving on hoist is the usual method of bearing diagnosis), engine/tranny and differential mounts. Differential noises are usually audible from outside the car but its worth looking into, or even driveshaft bearing noise.

[Frostedbutts]

Wow, thanks for the detailed reply! That's a lot more than I was expecting and definitely helpful.

The sound is certainly rotational and has a frequency, I could tap along to the beat of whatever noise it is making if I am cruising at a steady speed. It does not occur while stationary. It definitely resonates inside the vehicle while in motion, after driving it a bit more I can hear it the loudest through the shift boot/center vent area. With the windows down it is almost inaudible, which would lead me to believe it is something drivetrain related.

I think I may end up having to pay a shop to put it up on their lift!

[amnash]

Jack it up and spin the wheels. Did you look at the heat shield for the brakes? Sometimes they get bent inward against the rotor and it's an easy fix

[caliber676]

Sounds like it may be a transmission/clutch bearing. If you want to start diagnosing you will realistically need a hoist. Usually a shop will use a stethoscope while driving on the hoist or start disconnecting driveshafts, etc to isolate the area.

[leung23c]

Good info there^

[Skym]

I would think gearbox input shaft bearing or throwout bearing related.

This is an example of the throwout bearing noise sound -

https://www.youtube.com/watch?v=YWlK3sVXPyk

[curtisgoodman]

i have that ugly noise... it hasn't got louder or anything but its annoying... gotta drop the transmission to change that out i'm suspecting eh... also what would happen if it failed? just no more clutch or catastrophic failure?

[Frostedbutts]

It's definitely not the same sound as the video above, as it doesn't matter if the clutch is in or out. It seriously sounds just like a dragging brake but it is completely undetectable from outside the car so I doubt it's a brake.

[curtisgoodman]

steady bearing on rear driveshaft?

[Skym]

If dragging on the brakes there would be wear on the rotors.

Sometimes the stock brake hoses fail internally which creates that type of dragging noise and is hard to detect, except for excessive wear on one or more rotors (depending on how many brake hoses have failed internally).

[Frostedbutts]

bumping this...

After driving it a bit more I noticed it seems like it's louder on an incline/decline and especially around corners. I can't find the thread anymore, but I remember reading somewhere that would be more likely to be driveshaft related. Is that right?

[nismo-152]

Take a look at yuor driveshaft carrier bearing if you havnt already. It can play up in the bearing housing pretty good when worn out.