Funny noise... need help!

[Jerodcs]

When I'm at low RPM, low load in any gear--but most noticeably first and second--there's a grinding noise coming from what seems to be right behind the driver's seat. I'm assuming it's the transmission, but really have no idea.

To describe the noise: sounds like small gravel or sand being ground between two heavy, metal plates. It completely goes away as soon as I put my foot in it or go above a certain RPM (~2500), and not because the sound is masked--it actually stops making the gravelly sound.

It's really starting to ruin my first week with the car and I'm worried that driving it more might really damage something... help?

 

[steveny]

When I'm at low RPM, low load in any gear--but most noticeably first and second--there's a grinding noise coming from what seems to be right behind the driver's seat. I'm assuming it's the transmission, but really have no idea.

To describe the noise: sounds like small gravel or sand being ground between two heavy, metal plates. It completely goes away as soon as I put my foot in it or go above a certain RPM (~2500), and not because the sound is masked--it actually stops making the gravelly sound.

It's really starting to ruin my first week with the car and I'm worried that driving it more might really damage something... help?

So is it funny :biggrin: or funny which could turn to :frown: then and the cost to make it go away

I don't have a clue what it could be.

 

[Briank]

Check to see if your tires are cupped on the inside edge.

 

[Dhalsim]

tranny bearings?

 

[Jerodcs]

So is it funny :biggrin: or funny which could turn to :frown: then and the cost to make it go away

Hahahaha my girlfriend is laughing her ass off, as am I. She also just noted that this is my version of MySpace... and I agree. But it's much more fun. :tongue:

 

[Jerodcs]

Check to see if your tires are cupped on the inside edge.

Just did... they're very new so there's no sign of anything yet. What were you thinking it might be? Wheel bearing?

 

[HTN]

When I'm at low RPM, low load in any gear--but most noticeably first and second--there's a grinding noise coming from what seems to be right behind the driver's seat. I'm assuming it's the transmission, but really have no idea.

To describe the noise: sounds like small gravel or sand being ground between two heavy, metal plates. It completely goes away as soon as I put my foot in it or go above a certain RPM (~2500), and not because the sound is masked--it actually stops making the gravelly sound.

It's really starting to ruin my first week with the car and I'm worried that driving it more might really damage something... help?

Did you do a PPI before purchase?

 

[DrVolkl]

Any aftermarket parts on the car? (ie clutch)?

 

[damthatbeaver]

Hey Man...contact Drew and ask him about the tranny...I have an automatic so I cannot help you - but I would not do anything until you find out what is wrong with her...would hate to do any more damage - if there is any at all! How many times have you ahd her out? When did this all start?

Dam

 

[Jerodcs]

http://www.nsxprime.com/forums/archive/index.php/t-37709.html

He seems to be describing something similar...

"I'm getting a grinding noise more and more frequently in 1st and reverse. It has been increasing during the last month or so.
It never happens when I am accelerating normally. However, when being forced to play with the clutch at low speeds in traffic it happens. Only when I'm moving forward or backward very slowly, slowly depressing the clutch pedal this happens."

PPI inspection by Barney at Gary Force... said it was fine... but I know that if he had heard this it would not have been "fine."

HTN -- Starting to wonder if the shipping guys took it for a ride and broke teeth off of a gear in the tranny. It did have five miles more at delivery than at the time of shipping... but I figured the magnetic plate would catch loose teeth and save me from this noise.

Any more ideas? Starting to think Dhalism may have been right when he said "tranny bearings."

 

[Jerodcs]

How many times have you ahd her out? When did this all start?

Oh, and it started the second I got her... quiet enough that I thought it might be a normal NSX noise, but getting MUCH louder the farther I drive.

 

[goldNSX]

Sounds like the bearing next to the snapring. I've heard of at least two failures of them with similar sounds. And no, the snapring doens't have to be broken for this.

 

[RON98]

does the sound change clutch in or clutch out?

 

[Larry Bastanza]

When you are moving along in either first or second gear, if you blip the throttle does the shifter more at all front to back?

What are the last 6 digits of the VIN?

LarryB

 

[davidf]

Wow, 1st week and somethings wrong. I feel for ya man. But you do have some pros here helping you.

 

[mickeylex]

When you are moving along in either first or second gear, if you blip the throttle does the shifter more at all front to back?

What are the last 6 digits of the VIN?

LarryB

That's immediately what I thought when reading this thread. First and most obvious question: is it a tranny in snap ring failure range?

 

[goldNSX]

Those two German guys with the gearbox noise I know of had a snap-ring bearing failure WITHOUT a broken snapring. They said their gearboxes sounded in 1st and 2nd gear like a FIAT 500. They had this problem with about 90k miles and think that this bearing is the weak point in the gearbox. Again: Both had noises without a broken snapring but due to a bad bearing.

 

[davidf]

If you've only had the car 1 week I raise a little hell about.

 

[Jerodcs]

Last six digits of the VIN: 002197

I'm guessing you're referring to the snap ring issue--I don't have the transmission number on hand but was told during the PPI that it was out of range. Also, the shifter stays perfectly still in first and second.

RON98- with the clutch depressed there is no noise. It only happens when I'm moving, clutch engaged, very slowly, and at low RPM.

I'm starting to think goldNSX might be onto something.

Thanks to all for the help!

 

[goldNSX]

I'm starting to think goldNSX might be onto something.

Michael and Marek from Germany followed this theory and it's very plausible. Each of them changed this bearing themself, it's their honor. :wink: Michael told me that he would recommend changing this bearing while doing the clutch as it seems to be the weak point.

The following picture shows the bearing (courtesy to SlickWilli)

I don't want to route you the wrong way. I would check everything out before removing the gearbox.

 

[NSX-Appeal]

RON98- with the clutch depressed there is no noise. It only happens when I'm moving, clutch engaged, very slowly, and at low RPM.

No noise with clutch depressed? Sounds very similar to what I encountered with my Lotus Esprit. Turned out to be a bad throwout bearing. How long ago was the clutch replaced...or has it been?

 

[Jerodcs]

No noise with clutch depressed? Sounds very similar to what I encountered with my Lotus Esprit. Turned out to be a bad throwout bearing. How long ago was the clutch replaced...or has it been?

Someone else said the same thing about the throwout bearing... There's no record of the clutch having been replaced, so I'll assume it hasn't. Looks like I have some exploratory work to do this weekend...

 

[RON98]

from your info looks like your in TO.

im about 30 minutes away off the 5 freeway in Valencia. if you want to bring the car by i can take a look at it.

also if you PUSH in the CLUTCH and the noise goes away, it is usually not your throw out bearing.

sorry you to be the bearing of bad news.

when you push in the clutch, the throw out bearing gets 100% load and thats when it should be rocking and rolling and making the noise.

if the noise slowly goes away when the clutch is pushed in, it is a transmission bearing going out since the internals in the tranny lose their momentum and stop spinning and the noise goes away.:frown:

have you checked your tranny fluid? usually a leaking tranny with low fluid will result in bearing failure due to lack of lubication.

once again you can bring it by, i'll take a test drive and see whats up with your car.

also it could be a wheel bearing noise. if your sitting still and pushing in the clutch changes or stops the noise, its a tranny issue.

you can reach me at

888 285 2822.

rob

 

[Jerodcs]

RON98 - Thanks! I may have time to do that this weekend--I'll PM you.

Here's a new clue for anyone still following the thread:

When I disengage the clutch, there's a quick "thump/grind" noise as I push down with my foot. Don't know how I didn't notice it earlier.

Hopefully that helps lock it down to a particular bearing.

 

[RON98]

um... thud.

front or rear of the car?