Grinding noise in neutral
 

What could this be? Sitting in my drive way in no gear itll make a grinding noise but when I push the clutch in itll go away, it also doesn't make the noise when I go as far as I can tell

That's the throw out bearing, it's normal. If you get a screeching sound get it replaced. Until then turn up the tunes.

google "neutral rollover."

Is it a serious problem? Because i have that noise too.
Is it self fixable or do i need to take it back to toyota?

If the transmission doesn't make any noise while driving then there's nothing wrong.

Idle up to about 2K RPM. I bet the noise goes away.

So far i only hear it when its idling/neutral. What is transmission sounds like?
I have a N1 exhaust...so i cant hear if the noise goes away or not....

I just try with my dad rev about 2000rpm,, the rattle noise still exist!

Do you have a lightweight flywheel?

Everything stock beside drop in k&n air filter and invidia exhaust.

Very few mechanical things that go bad ...... fix themselves, including a bad TOB.

I'd suggest you pay a visit to your dealer and ask to listen to another FR-S for a comparison. While you are there, you may consider asking a tech for an opinion.


humfrz

Most manual transmissions, when the clutch is NOT engaged, have a shaft(s) that rotate. This is a "transmission" sound, some call it a "rollover" sound.

It kinda sounds like a quiet clothes dryer, running on low speed, when it's empty.


:iono:


humfrz

I mean as long is normal,,then i am fine with it.
I just did a little bit research right now,,many people say its a high pressure fuel injection, and its normal. so i dont know...

It's probably a good idea to have a dealer tech give it a listen. A little neutral rumble is no biggie but who can say when it becomes excessive?

We're specifically discussing the sound of the transmission in neutral. this sound will disappear when you push in the clutch. If it doesn't disappear then it's not the transmission.

sorry...i dont have this problem...

But i do have the rattling noise problem when idling/neutral.

If you haven't already done so, you will find that the FR-S can make lots of "unfamiliar" sounds.

Yes, one of them is a TOB going bad. It goes from silent to whirring to grinding to screeching to howling (as it stops and is pushed into the rotating clutch pressure plate fingers).

Another common sound is the HPFP (High Pressure Fuel Pump). It can be silent .... it can tick ... it can chirp (like crickets) ..... it can go rat-a-tat-tat ...and many other sounds ...... depending on type of fuel, temperature, engine speed (fuel demand), and phase of the moon (seeing if you're payen attention).

Like my oncologist tells me ....... "no change is good"; so, if sounds don't get any louder/worse, your car is most likely OK.


humfrz

yea its has the chirp sound when idling, other than that everything else is fine. well,,700 miles until 22500 service. Just have to live with it for now.:popcorn:

Thanks guys

If the sound is the HPFP, it doesn't mean it's going bad. Some of them just make that sound.

Here's what I tell some folks:

Yep, that sound you hear is the ultra-high pressure fuel pump. In fact, the engine requires two fuel injection systems to keep up. You see, the engine sits in there, flat, like a Porsche engine and has a really high compression ratio; even calls for gas with a higher octane rating that is found at most pumps.

Why? Because racecar. .......... :popcorn:


humfrz

phew,,thought it would be something serious.:cheers:
Lol u sounds like the guy with the simpson icon!!!

Ohhhhhh...........I hope he don't see that comment ....... he will be really pissed ...... :mad0259:


humfrz

oh Jesus. i am glad he is sleeping right now, and i hope this this post will sink. :bonk:

I don't think so. The TOB should only be spinning under load when the clutch is pushed IN. With the clutch out it's just sitting there between parts and should not be spinning, therefore not making noise.


Trannies have an input shaft that spins whenever the clutch is out (engaged). If the bearings on that shaft go bad it makes noise.


Have a tech listen to your car-- some slight noise is normal just from the gears in the tranny spinning when the clutch is out, but it should not be a grinding noise.

Well now, @pantdino , back in the 80's or earlier, you would have been correct most of the time.

I had the same misconception until ol @Ultramaroon enlightened me.

The TOB in our cars is an "active" type, meaning it's spinning any time the engine is running. True, it's under pressure only when the clutch is pushed it.


humfrz

What is the advantage of that? Instead of spinning like 1/10,000 of the time it's spinning 100%. I guess they figure if its not under load it won't make any difference? But spinning still creates heat and uses up the grease in the bearing.

Well, now, @pantdino , that's an interesting question and one that I had.

Some ol boy somewhere on the interweb explained it this way:


"On "older" cars (prior to about 1980) the clutch system used "free play", i.e. there was a small gap between the throw out bearing and the pressure plate fingers, when the pedal was up (clutch engaged). Throw out bearings were not designed to run a lot, and these bearings could not compensate for mis- alignment.

Starting in the early '80's most clutch systems switched to "self centering" throw out bearings. At the same time, the clutch systems changed from "free play" systems to "constant running" (in other words, the throw out bearing was in constant contact with the pressure plate fingers, and always turning) systems. And they also incorporated self adjusting systems in the release linkage or pressure plate itself."


Now my (humfrz) take on the situation is that, most, back in the day clutches, were dis-engaged with mechanical linkage. So, the TOB was set close to, but not touching, the fingers of the pressure plate. So, when the clutch pedal was pushed down, the fork pushed the cold, non spinning, TOB, against a bunch of steel fingers that were rotating at the speed of the engine.

Talk about a "cold start" and a sudden temperature change...... :eyebulge:

Now with the hydrolytic clutches, the inner workings of the slave cylinder puts a 5-15 lb/sq/in pressure on the TOB which keeps it in constant contact with the rotating pressure plate fingers. So, it stays warm by spinning all the time the engine is running. When the clutch pedal is depressed it is called upon to "work" by pushing the pressure plate fingers, thus releasing the pressure on the clutch disk.

So, which would the bearing rather do ...... spin all the time and work when called upon ........ or sit there cold and get slammed up against steel fingers spinning at several thousand RPMs .... every now and then....... ??

If I don't have this completely straight, I'm sure ol @Ultramaroon and maybe others, will chime to correct me ...... :D


humfrz

Yessir. That's better than I would have done. Part of that magic is, as you mentioned, the self-centering feature of the TOB. Without that, the whole thing would end up a pile of dust in short order.

I just noticed this light spinning noise when all my raido and AC is off. when idling at stop, i hear this and noise goes away when clutch is in.

Input shaft spinning in the transmission. Normal.

everyone talks only "it's your TOB" shit so i was like wtf. lol

If the TOB is going bad you will hear it ...... it will howl or screech at you .....;)


humfrz