Whine-like noise from disengaged clutch

[classic cars]

I had a 6-speed NSX-R box installed on my 91 last week and everything went well. As you may know, the NSX-R 6-speed box works with the double-plate clutch, so I did not need replace my OEM clutch, which is almost new anyway (3000 careful miles)
But now I get a strange high-pitch whine when I press the clutch pedal.
I get absolutely no slippage from the clutch and everything else is fine.
To describe the noise I would say that it sounds like a bird...in a very bad shape
The noise follows the engine RPM. From time to time it disappears completely, but it always comes back after a while. It makes no difference if a gear is engaged or not.
The noise is really loud to the point of becoming embarassing in a parking lot.
What can it be? Could it break down to the point that I need to tow the car?

Any help is appreciated.

Thanks
Mike

PS I will report on the gearbox experience in a separate thread.

 

[Autophile]

That sounds like the throw-out bearing. I hope it isn't, though, because replacing a throw-out bearing could be a lot of work.

 

[classic cars]

If it is the throw-out bearing, can it be related to the installation job of the new gearbox? It was done by a Honda dealer, but I am surprised to see the bearing damaged now as it was absolutely perfect before.
It could be a coincidence, but...
Are there any "typical" mistakes that can be made during a gearbox swap and that can lead to the throw-out bearing failure?
This information would be very valuable to me as I may try to get the bearing replaced at the dealer cost, if the damage was caused by them.
Thanks
Mike

 

[Larry Bastanza]

I agree with Autophile. Your tech will be very sad, since he will most likely have to pull the transmission out again. Was everything quiet with the 5 speed? Also does it "chirp" everytime you press the clutch, like in between shifts?? Was the throw out bearing replaced? It is odd that it would be a problem just by changing the gearbox.

The only possibility I can think of is that there is little or no grease on the inside of the reinstalled throwout bearing. It is not really all that likely though. Unless the NSX-R has a different setup. I did not think it did.

Good Luck.
HTH,
LarryB

 

[titaniumdave]

I thought the 5-speed stock double plate clutch would not work on the 6 speed transmission with out changing the input shaft because the splines are to short on the 6-speed shaft for full engagement of both disks. Is it different with the type-R? I know Exedy makes a double plate clutch which will work with all trannies, but it has an intermediate carrier the disks engage on that then engages on the splines of the input shaft.

If the problem is the throw out bearing there should be some effect on the sound as you apply the clutch. maybe even a feeling throught the clutch pedal?

 

[classic cars]

Yes, everything was quiet with the 5-speed.
What I noticed immediately after they gave me the car back was that the clutch release was *slightly* less smooth than before, the action was just a bit "discontinuous" as opposed to perfectly smooth.

Is it possible that they mis-alligned something during installation?
Would this explain the immediate loss of smoothness and the failure of the throw out bearing after approx. 400 miles?

BTW there is no noise at all when I start the engine from cold, but the noise comes back after a few clutch operations. Is this normal with this type of failures?
For the sake of completeness, there is no noise at all when the clutch is engaged, i.e. when the pedal is not pressed.

 

[Autophile]

What I noticed immediately after they gave me the car back was that the clutch release was *slightly* less smooth than before, the action was just a bit "discontinuous" as opposed to perfectly smooth.

Is it possible that they mis-alligned something during installation?
Would this explain the immediate loss of smoothness and the failure of the throw out bearing after approx. 400 miles?

Well, misalignment is not the problem, as I see it (It is centered axially, so there should be nothing to misalign). It seems to me that the geometry of the bearing fork has changed, and perhaps there are different load angles on the bearing face than what it had when it was broken-in for the first 3000 miles. Larry, straighten me out if I'm off base here. The bearing was replaced with the new clutch, wasn't it?

BTW there is no noise at all when I start the engine from cold, but the noise comes back after a few clutch operations. Is this normal with this type of failures?
For the sake of completeness, there is no noise at all when the clutch is engaged, i.e. when the pedal is not pressed.

My Toyota daily driver is currently giving me the throw-out bearing whine too. It only happens about once every 30 presses of the clutch pedal. So, the intermittent noise is consistent with this type of problem.

 

[classic cars]

Thank you Larry and Autophile.
One more question, does this need urgent attention or can I still drive a few more weeks? In other words, is this aproblem that can stall me somewhere?
Thx again
Mike

PS for Titaniumdave. The NSX-R box is different from the normal 6-speed. It comes with the longer shaft and double inlays. In fact the NSX-R uses the double plate clutch of NA1 as it was considered to be stronger.
In addition it uses a shorter final ratio, 4.235 instead of 4.062.
There is a beautiful Honda website about the NSX-R with lots of info.
I got the link from here, so it's not new, but for those who missed it, here it is:
http://world.honda.com/NSX/

 

[Larry Bastanza]

Mike,

You are asking me to look into my "Crystal Ball". I really cannot say for sure, if a few weeks of driving is OK. The bottom line is something is not correct with the installation.

Was the throw-out bearing replaced with the new clutch 3K miles ago? Maybe your tech should investigate the clutch fork to insure it is in place correctly. I am thinking it would not work at all, but you never know.

Also, was this noise there immediately when you picked up the car, after the trans swap??

HTH,
LarryB

 

[classic cars]

Thx Larry,

• I don't know if the bearing was replaced because the clutch job was done by the old owner when he sold me the car.

• No, the noise was not there after the box swap. It started approx. 400 miles after.

I still can't understand what may have caused this failure. Any idea?
I will take the car to the workshop this week and avoid any delay.
Thank you again
Mike

 

[Larry Bastanza]

No, the noise was not there after the box swap. It started approx. 400 miles after.

With this new info it is unlikely, but possible this is a part failure.

Keep us posted.

Thanks,
LarryB

 

[classic cars]

Hi friends,

I took the car to the workshop.
The tech confirmed it's the bearing. I asked for a discount on labour time considering the circumstances.
The manager agreed to take 2 hours off the bill. That will probably mean 6 hours instead of 8, plus the parts of course.
I'll keep you posted

Mike

 

[Larry Bastanza]

Mike,

With the understanding that the shop did not install a "NEW" bearing, but used the one in the car with the clutch that was installed ~3K miles ago, getting a 25% discount on the labor seems fair to me. It is always more difficult to negotiate warranty if the shop does not provide ALL parts for a job.

Glad it will be taken car of for you.

Regards,
LarryB

 

[classic cars]

Re: Whine-like noise from disengaged clutch --PART 2 !!

Ok,
so the car went to the shop. The release bearing was replaced. But a few minutes before I get there, I receive a phone call and the tech says...the whine is back...
And so it is. He was very embarassed. The bearing was replaced with a new one...
However there is a difference. The noise is only present when the engine is cold. After a good drive it's silent.

I'd like to repeat what the problem is: I get a whine when I press the clutch pedal completely, i.e. when the clutch is disengaged. If I release the pedal there is no noise at all. This sounds like the typical release bearing problem, but as I said we replaced it and it's still there, albeit a lot lighter.
The good news is they let me go with no charge, but I had to promise I will come back and leave the car until it's properly sorted.
The tech says it may have something to do with the NSX-R gearbox we've just installed, but what?
Can anyone help? what can it be?
One more thing: 2 springs out of 4 on the first clutch disc are a bit loose, any hint maybe?

Thanks

Mike

 

[Autophile]

I'm sorry to hear that, Mike. Does the noise sound the same, aside from happening under slightly different conditions? If it has the same pitch and intensity, then maybe the bearing was not the problem.

Internal tranny noises and loose plate spring noises are out of my scope of experience. Hopefully Larry, or another knowledgable person, can help you find the answer. Best of luck.