msenzo

Dear members
I have observed that when the car is on neutral, if I press the clutch, there is a discernible change in engine note, as if something stopped moving. When I release it, the engine note changes as if something is now rotating.
Otherwise the car is fine
Anyone experienced this? Is it normal?

TownDrunk

Normal

shaunv74

It's the throwout bearing for the clutch. It's happens to all of us. It's noisy. It rubs against the fingers on the pressure plate.

swoope

iTrader: (5)

when you push in the clutch the input shaft for the transmission stops rotating.. when you let the clutch out it starts turning again...

that is what you are hearing..

beers

NgoRX8

iTrader: (1)

don't worry, nothing is broken

~0zzygirl~

I've read tons of threads on this... It seems some people think it's throw-out bearing noise and some think gear rollover. From the descriptions, it seems like we are all talking about the same noise, most of us have it, and it's harmless.

So who can say for sure, is it clutch or tranny?

TomAssBender

I'm not advanced enough to know what a throwout bearing is, but I do know how a clutch works, and it makes sense to me that there would be a change in note. As swoopse said, even if its in neutral, the input shaft is still spinning

~0zzygirl~

You and I have talked about the squeak that my throw-out bearing is making. So the "grinding" is also throw-out bearing? What about all the people who say that it is quieted after changing out transmission oil to redline or royal purple? You had a new clutch, right... did your grinding noise go away?

Yusik

Have same annoying noise as all of us, its gear box bearings' free play, changed oil for best available and reputed among racers in Europe - Motul 75W90 GL 5 full sinthetic, - no any changes. Two ways left - either add some additives, or leave with it. Don't know if somebody has experience with any aftermarket gearbox additives?

shaunv74

I switched to Redline MT-90 for transmission fluid which helped a great deal with the smoothness of the gearbox (didn't really notice any gear noise). I have not heard about any additives. If you've already done this and you still have noise it may be clutch/throwout bearing which would not be affected by what you put in the tranny. I don't know if any of the aftermarket pressure plates have more clearance with the throwout bearing when the clutch is engaged. Maybe ask on some of the threads on replacement clutches.

~0zzygirl~

I forgot to mention... I marched into the dealer service unannounced with that TSB and he said, Yeah but this is for 'hard to release' and yours is just a squeak. I said, yeah but i think that it is part of the problem and will eventually lead to this.

Then he said...


You need a new engine. *insert smiley with jaw on floor*


Anyway, did your chatter stop after a new clutch or what?

MazdaManiac

iTrader: (3)

Uh, no.


Uh, YES!

Uh, no. Again.



Think of it this way:


Foot in ***, tranny make noise. Bearing not doing anything.
Foot on pedal, tranny make no noise. Bearing working.

That is normal.

Foot in ***, tranny make no noise. Bearing not doing anything.
Foot on pedal, tranny make noise. Bearing go bye bye.

That is a failed release bearing.

The release bearing (sometimes incorrectly called a throw-out bearing) is only under load when you press the pedal. If the tranny makes less noise with the bearing loaded (pedal in), then it can't be the bearing.
All manual transmissions make this noise - it is just louder on the '8 and the Miata because of the design and the lack of insulation.

Now, the pilot bearing is another issue, but that seldom fails under normal use.

LionZoo

You may want to reconsider GL-5 in the transmission as some GL-5 oils are bad for synchro life.

MazdaManiac

iTrader: (3)

Yeah, stick with GL-4.
I use Redline (a 50/50 mix of MTL and MT-90), but Royal Purple is good, too.

Yusik

I've seen specifications of Motul Gear box oils, its are GL4-GL5, see picture attached. Phoned to oil expert from Motul dealer too, they never heard that GL5 can be bad for synchro, its just nonsence! GL5 is with improved spec of GL4 and cannot be bad, just otherwise. May be, there some misunderstanding between specialists of US oil brands and European ones.

By the way Motul has now new gear box oil: Competition 75W140, excellent new spec, I'll try it when spring come

shaunv74

Hmm. You learn something new every day. About the release bearing I mean. I always thought that was the throwout bearing. I thought it was chatter against the pressure plate fingers since there were wear marks on my pressure plate in the shape of the bearing when I inspected it during installation of my AL flywheel.

shaunv74

Yusik: I used a Lucas oil GL-5 product in my Trans for a while and was disappointed in the cold weather performance. It was definitely harder to shift from 1st to 2nd when it was cold. I don't know much about GL-5 vs. GL-4 specs, maybe it is better at higher temps and not as good at lower temps. Sometimes that is the case with racing products. Again don't know but just thought I would share my experience.

Please let us know how it works though. I think we're all up for hearing about new things and people trying them out!

Yusik

I don't know what kind of oil was in my tranny when I get the car this summer, I changed it for best available and reputed - Motul, you know it was -10c(14F) this morning, no problem with shiftng, as smooth as in summer!
The difference in quality of oils, I think, in quality and quantity of additives, the price tells you everything: its about 15-20$ per liter(little bit more than quarts), I don't remember exactly. So, if Motul promised an easy shifting in our atitudes and best protection for hard usage, you can be sure in it.

msenzo

Thanks for all the input, was worried there for sometime. Being totally blank on clutches I went to http://auto.howstuffworks.com/transmission.htm. From what they say and the pictures they show, I thought when the engine in running and the clutch is not depressed, the whole mechanism rotates, but the shaft "to differential" is not rotating because no gear is engaged. When the clutch is depressed, the whole mechanism stops rotating because there no contact with the rotating engine. But it still doesn't explain why the Golf 4 would not exhibit the same noise change when the clutch is depressed in neutral.

Otherwise, the most important thing is that this is the same with all the 8s, hence, it is normal.
Happy revving !

mikeschaefer

hah yea try driving around without the shift boot installed.... then put it back in and it won't seem as loud anymore

swoope

iTrader: (5)

the trans in the rx8 is about 24" from your ear.

is not the golf transverse drive.. the clutch and pp and trans are no where you...

beers

Macrotor

This is why I love being an 8 owner and being apart of such a great forum. All the answer just a few clicks away! Been everywhere else and have been missed lead up until now! I'm new to the 8 game and I'm loving it!

Keep up the good work guys

yiksing

@Yusik

I've recently swapped out Mobil 1 SHC GL-5 gear oil and is running Redline MT-90 GL-4 atm. I did not experience any problems with the Mobil 1 besides unable to shift into 1st gear unless I come to a total complete stop. In my opinion and from observation and what I could find on the Internet (taken with a grain of salt) I doubt its the EP in modern GL-5 thats killing synchro but its the friction modifier that makes synchro unable to engage properly that kills the tranny.

adamwzl

iTrader: (3)

majorrr thread revival!




@yiksing, you know this thread is about 4 years old correct?

VashGS

Hum Rx8 has a normal light sound when clutch is out and in neutral. The pad is pressing against the flywheel. And the engine is VERY close to the driver in this vehicle. This is why it might sound odd for someone used to a vehicle with the engine and trans more forward. The motor is small and it's mounted to give near 50/50 warrior like precision. When you mod your exhaust you won't hear it prob Also audio pilot should cancel that out for the most part.