Loud Hum/Grinding Noise + Vibration in 5-15mph gear range, in gear and rolling neutrl
 

Hey guys, so after a solid night driving around with the buddies, she ran so perfectly for hours I could marry her.
The next morning, leaving my house at about 5mph I started to hear a reaaaally loud what I'd call a grinding but my buddy calls a hum in 1st gear.
It started at about 5mph when I drove really carefully and carefully got the gear to bite and really took my time. On top of the sound my clutch pedal (and maybe brake pedal) were vibrating with it.
First step was to put the clutch all the way in, as I continued to roll forward, the clutch all the way in did not stop the noise, nor did the clutch all the way out in gear. So I fully braked and as I came down to about 4mph in my brake it stopped, and I came to a complete stop. Now this will ONLY happen when I drive slow, if I rev up to 1600 or anything above in first it doesn't give me the issue, and it can only EVER be heard in 2nd gear if I shift to second after it starts in first.
So after all this, I felt pretty solid it was a clutch issue. Then leaving the gym I rolled forward down a maybe 2 degree hill maybe 3 feet forward in neutral, and it happened again. No gas, no clutch engagement, maybe 3 feet travel.
My car has 14k miles, but the tranny was replaced at 9.8k.
Only performance parts is catback and bilstein coils.
It's a 2014 brz

I'm going to go ahead and attempt to post a few clips of the noise.... Suggestion on how to upload video from phone?

Clutch. I had mine upgraded to ACT flywheel and clutch kit. Twice as loud now. I think it is just the nature of the car. Changing fluids in transmission help.

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not nature... this is a VERY loud sound lol. i wish i could figure out how to post a video... it almost drowns out my music at 30

Hello @jakebrz and welcome to ...... The Forum ....... :clap:

Yep, this place is full of keyboard mechanics ........ I'll start........:)

That sound could be coming from the notorious throw out (release) bearing.

That bearing in this car is always turning (as long as the engine is running) regardless if the clutch is engaged or not.

So, if the bearing is running dry and/or is defective it could be making noise all the time your car is running.

When its NOT under load (clutch pedal up) it can make a different noise than when the clutch pedal is pushed in (under load).

You may wish to have it checked out.


humfrz

PS - the only way I know how to post a video is to put it on a host site then reference that site.

Thanks for the response!
few questions...
why would it only be happening in that lower mph range?
also, with a few handy friends do you think i could replace that bearing myself?
lastly... how urgent of an issue would you predict that to be?
i'm going to have to do some research on that now, thank you

If it is a bad bearing it may be only howling at a low rpm because once it gets going, it may warm up and settle down because it's spinning faster.

As far as urgency, that all depends. It could go that way for several miles or it could seize up within a few minutes. If it seizes up, the clutch fork could push the frozen bearing into the fingers of the pressure plate (which are spinning) and grind them down till they fly apart and jam the clutch disk which would blow it up and mess up not only the pressure plate but possibly scar up the flywheel.

Can you replace a faulty throw out bearing yourself .. ?? Of course you can.

* jack the car up or put it on a hoist
* acquire or fabricate a transmission lift/jack
* unbolt the driveshaft from the transmission
* disconnect the clutch slave cylinder
* unbolt the bell housing from the engine
* unbolt the transmission mounts from the frame
* pull the transmission off the spline
* examine the flywheel for damage
* replace the clutch disk and pressure plate (might as well since you're there)
* examine the clutch fork (lubricate if it's OK)
* replace the throw out bearing
* disconnect anything else I forgot to mention..... :iono:
* put it all back together ...... see how easy ......(NOT!)...... I've done it several times.

OR

Use the humfrz method ....... drive or toe the car to the dealer (if under warranty) or a local transmission/clutch shop.

Ask them to figure out what is wrong with your car and have them fix it .......:respekt:


humfrz

Thanks a ton for the help! I'll go ahead and make this todays project..
Unfortunately she's definitely not warrantied anymore lol.

How is 2014 BRZ with 14k miles not warrantied anymore?

Tuned (flashable back to base tune, if i wanted)
coilovers
headers/catback
camber bolts i suppose would do that too

Ah, I see. I don't know why I haven't thought about mods. :thumbsup:

If those mods are not transmission related, it shouldn't affect warranty. I'd flash back to stock just to confirm noise is unrelated to flash.

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Doubt it, I'm using openflash performance tablet. & my warranty is bullshit, any performance mods void the entire thing. Trust me, it's been a big war

:(

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If anyone else has any insight other than the clutch release bearing please do tell:)