This has been driving me nuts for a while now.

If I crank up my car in the driveway, I usually hear this metallic growling sounds in neutral...sounds like a bad powersteering pump or pulley.

When the growling sound occurs...it moves up in pitch along with the RPMs.

If I put the clutch pedal in, the sound immediately goes away and all you can hear is the exhaust tone. However, releasing the clutch immediately causes the sound.



Now for the strange part:
When the sound is occuring, if I move the car forward just a tiny bit, the sound goes away completely. If I move forward a tiny bit more it returns. Move forward some more it comes back. Move forward another foot, it goes away! WTF?


To Recap:
-Growling/rattleing sound occurs in neutral
-goes away with clutch in
-goes away/comes back depending on position of the car.
-only happens in neutral and not in gear.


My current guess:
Has something to do with the driveshaft? Driveshaft only turns with the clutch up and car rolling....if you are in neutral and you coast, the driveshaft is turning right? Well at some point along the rotation, the driveshaft is contacting something and causing the rattle? The contradiction is why does the rattle raise with the rpms?

 

Got video/sound?

 

I have had the same problem in mine, and have seen it in others. so +1 for an answer on that subject!

 

sounds like it your throw-out bearing might be going out... all cars do it. but when you push the clutch in and it goes away that is almost a 100% t.o. bearing issue.
my 240sx does the same thing right now.
it goes with the engine rpms goes away when i push in the clutch immediately and returns when i let it out again. btw throw out bearing is connected to the transmission.

the throw out bearing engages the pressure plate. idk how they are on the fd but most of them are packed with grease, if the grease is gone you hear the noise.

i hav also heard of people driving on a bad one for over 60k miles with no problems its just annoying.

 

bingo.

 

A whining sound that increases with RPM might also be your diff. I thought my transmission sounded like a dogbox after a really hard track day but it was a diff seal that blew and drained the oil so my diff was toast. However, since it happens with the car stopped as well, its probably the above stated.

thewird

 

yes, but the part that screws this all up:

If the car is making the rattling throwout bearing noise, and I coast forward like 2 feet, the noise stops COMPLETELY. lol I can rev up and down, clutch in and out, no noise. Makes me think its something with the diff or driveshaft...I"m going to check the fluid I guess.

 

Def sounds like TO like someone said although i heard on some clutches (like ACT for example), that sound is normal.

I had my TO replaced 3 years ago and i have had a sound prior to the TO replacement and even up to now a noise when clutch is not engaged.

Its not really a metallic rattle sound but its almost like a low, shhhhhhhhh sound. And only happens at idle. Its not dependent on rpms.

 

the fact that it goes away when you engage the clutch points to the TO bearing. up on a lift time....

/\ that may be the input shaft 1qwik..

 

well why would it go away COMPLETELY when I move the car forward 1ft? That just doesn't make any sense.

 

It can't be driveshaft if it can happen while you are sitting still.

Throw out bearing, or pilot bearing.

 

I'll offer a guess:

Since it is also related to trans output shaft position, it might be a slightly loose bearing on that shaft that, due to its specific wear, changes clearance due to position, affecting whatever in the trans is rattling.

Dave

 

I'm going to go with either a worn TO bearing or a damaged clutch. The rattling/grinding/squealing noise that you described sounds like something I did to the clutch on a ranger I had in High School. Drove it too hard (yea, yea, it's a ranger....) and broke the springs and metal in the hub itself. It made an angry rattle/squeal. The clutch is less likely than the throw out bearing (unless you abuse the **** out of your clutch), but you never know.

 

I do not abuse my clutch at all....its a stock clutch and I'm running 258rwhp around town. I do not shift hard or fast and NEVER launch.

So what if my TO is making noise? Is this really that bad? Like should I be pulling all the **** apart and replacing it?

 

the throw-out bearing is easy... if you are comparing it to a main-shaft bearing in your transmission.

 

still don't understand why it would go away completely if I move forward or backwards a foot.

What should I be doing to diagnose this...remove inspection plate and look for something?

 

Wait. So the sound goes away from hearing the noise at stop, then after you move foward? Like no more sound after the initial movement?

Or does it make the sound ANYTIME you stay stationary??

 

Throwout bearing is either bad, wire ring bent and rubbing against clutch fingers or both.

Final answer !



Later

 

That doesn't, IMO, explain the relationship to the car moving a foot or two...

Dave

 

ok ill give it to you in detail.

1. car is idling normal at 900rpms....rev up engine, sounds normal

2.friend pushes car forward a few inches, a faint metal/rattling sound occurs...rev engine and it raises with the rpms

3.push car forward a little more and it gets louder...rev/raises

4.push forward a little more and it gets quieter

5.push forward a little more and it disappears


I can literally roll backwards in neutral at a hill and hear it go chahahah...chahaha.....chahaha....chcha,chaha,chah a, and the faster I roll the faster the sound passes from noise to quiet. Eventually it just blends in with the car as you are driving. WTF.

It almost makes the believe that the inside of a wheel is contacting something thats trasmitting a vibration from the motor...but that would make absolutely no sense at all.

 

First, I would determine if it is actually the clutch of the diff.

How to do it? Reverse Load on the transmission itself. **Clutch in, first gear, drop clutch right before vehicle stalls, but of course do not let it die on you, listen for noises from the rear. And do the same thing with reverse. Keep doing this back and forth, back and forth. If you hear a clunking metallic noise coming from rear. It is the diff.

Second. If you hear 2 different noises here, this can be both caused by: Diff + components inside clutch assembly.
Now if you figured out that noise is NOT coming from Diff, most likely you have it from clutch.
Here is a link CLUTCH explains how the clutch works and at 0:52, there is a small animation that shows how your clutch engages and disengages. That is when you actually hear your "metallic" noise.

Here is the article that shows you how exactly what every component work together to get the clutch working. CLICK HERE

So after reading all that, you should have a basic knowledge of how it works. Lets get back to our diagnosis.

I want you to perform these tests:

"If you find that your clutch has failed, here is an at-home diagnostic test that anyone can perform:

1. Start your car, set the parking break, and put the car in neutral.

2. With your car idling, listen for a growling noise without pushing the clutch in. If you hear something, it's most likely a problem with the transmission. If you don't hear a noise, proceed to step three.

3. With the car still in neutral, begin to push the clutch and listen for noise. If you hear a chirping noise as you press, it's most likely the clutch release, or throw-out bearing. If you don't hear a noise, proceed to step four.

4. Push the clutch all the way to the floor. If you hear a squealing noise, it's probably the pilot bearing or bushing.

If you don't hear any noise during these four steps, then your problem is probably not the clutch. If you hear the noise at idle and it goes away when the clutch is pressed, it may be an issue in the contact point between the fork and pivot ball. "

The above diagnostic test was found under http://auto.howstuffworks.com/clutch2.htm . It explained better than I do, therefore I just copied and paste it so it make it easier for you to diagnose.

Hopefully this can be helpful and a little tip into your knowledge of how the clutch work and how all it's component can be diagnosed during the operation of the clutch engaging and disengaging.

If you have any other questions feel free to PM me and I am more than happy to help you out diagnosing this problem. I am personally a Tech so I hope my words are worthy of your time =) Happy diagnosing.

Cheerings,
AzEKnightz

 

When you go forward, this sound can be connected to your "drive-shaft to differential" problem. This also needs to be diagnosed different.

But if it is the "same" noise that you have, I can think of 2 things right now, is your Throw-out bearing is going bad or you might have some "broken fingers" from you pressure plate that is hanging at the bottom of the bell housing, which can in terms explain why sometime it does it (the noise) and sometime it doesnt by position.

After performing the above test that I've stated, if confirmed. I would either, do another test to see if the clutch is slipping or not. If so, great, get yourself a new clutch kit that comes with a throw-out bearing, pilot bearing, clutch assembly and just replace the clutch. If not, its up to you to open it, see what's irregular and replace components as necessary.

Hope this can be helpful =)

-AzEKnightz

 

OK. Another 2 questions to help in the diagnosis:
1. exactly how far does the car have to move between making the noise, being quiet, and then making the noise again? If it is one wheel revolution (~6 ft.), it is almost certainly something related to the wheel or halfshaft position. If it is about 1/4 of that distance (1-2 ft.) it is related to driveshaft position.
2. Where does the sound come from? Front, rear, or middle of car?


Related to your thought that I labeled "A", I think, in this line of reasoning, you are basically on the right track. Let's try to narrow it down for source. Possible vibration sources can be bent brake-rotor splash-shield contacting rotor, etc. Anything that can vibrate near a wheel or halfshaft is a suspect.

Dave

 

Raise is up and look underneath really close for:
PPF damage
drive shaft and exhaust rubbing the tunnel braces or anything else

Bottomline: Something is obviously making contact depending upon the position of the driveshaft or lay of the land and the more the engine vibrates (as idle increase) the worse it is. I've never heard a DIFF rattling while sitting still so I don't think that's it and if it was you'd certainly hear some major problems while cruising.

 

Monster - put the car on racks, pull the inspection plates off the bottom of the clutch housing and do a through inspection with a strong light. With the vehicle secured, start it and run your clutch in and out.

Later