Originally Posted by idkwhatimdoing (Post 3025554)

Hi everyone,
I’ve had my Scion since October of last year, I’m not sure when this issue started exactly but it’s been pretty consistent in its presentation for at least a few months. I took the car to Toyota and they told me they could not recreate the noise even with my explicit instructions. At first I thought it was the throwout bearing, but I’ve noticed the crunching noise only appears in 2nd and 3rd gear, with 3rd having the loudest crunching that lasts from about 3k down to 2k-ish rpm (2nd tries harder to keep the noise down, it only crunches a little towards the end of 2k rpm).
When I’m driving through, say, a residential area in 2nd or 3rd gear and let off the gas, the car still in gear and the clutch still engaged (pedal up), there is a loud sort of crunching noise that resonates from the engine bay, can’t pinpoint where exactly it’s coming from though.
I thought it wasn’t an issue at first and that it was just in my head until I saw pedestrians cringing at my car as if it were a racist joke.
I appreciate any input anyone can provide, it is a model year 2015 FR-S, 6MT, ~41k miles. No mods.
Thanks!!


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Originally Posted by idkwhatimdoing (Post 3025932)

Thank you all for the replies, I apologize for not getting back sooner. It’s been raining heavily here and I can’t get a good recording of it yet.
I’ve checked the undercarriage and nothing is dragging. @humfrz thank you for the reply! The noise seems to occur when dropping from about 3200 rpm to 2000 rpm, and the noise stops when I push the clutch in. The noise also doesnt appear if I maintain a little throttle, the noise starts as soon as I let off the throttle while still in gear and clutch is still engaged. Also, there is this little rotational sound that comes from the engine at idle and when the clutch is pushed in the sound goes away (it’s almost like a little whine).


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Originally Posted by humfrz (Post 3025939)

Well, it's a good thing ya'll are finally getting some rain down there ..... to put out your wildfires ...... :thumbsup:

I see where ol @Tcoat is calling a bad TOB.

ol @Ultramaroon ain't gonna speculate till he hears a audio tape. Ya reckon you can get one of those ..??


humfrz

Originally Posted by idkwhatimdoing (Post 3025950)

Just went out on my lunch break to try and get a good video of the sound... that didn’t work. Damn rain makes this tin can sound like, well, a tin can.
Will try and get a better clip later if the rain clears up, the only way I can describe the sound as of now is a sort of diabolical metallic laughing noise (my TOB must be amused). @Tcoat @humfrz


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Originally Posted by Tcoat (Post 3025952)

Mine laughed all the way to the bank!


Woah! That’s one way to turn a bearing into a bushing...
I have never been so disappointed in a team of engineers
I’ll take it to Toyota this week and have them kindly check the bearing while I’m still under warranty.
Will update everyone on this issue, maybe I can maybe bring an end to this happening on our cars.
Thank you all for your help!! @Tcoat @humfrz especially;)


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Originally Posted by Tcoat (Post 3025952)

Mine laughed all the way to the bank!


Woah! That’s one way to turn a bearing into a bushing...
I have never been so disappointed in a team of engineers
I’ll take it to Toyota this week and have them kindly check the bearing while I’m still under warranty.
Will update everyone on this issue, maybe I can maybe bring an end to this happening on our cars.
Thank you all for your help!! @Tcoat @humfrz especially;)


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Originally Posted by FirstWinter (Post 3026077)

If it is the TOB try to get the 17+ replacement along with the grease. Now I'm paranoid as well since I have a 2015 and at ~41K miles just like you.

Originally Posted by humfrz (Post 3026219)

OK, good, so, we can get a bore scope in there......:thumbsup:

I wonder if a scope can be placed in there to see the TOB while the engine is running .. ??

If so, I wonder if a TOB bearing, that is going bad, would wobble or smoke or show any other signs of getting bad...??

Let's brainstorm this possible diagnostic method to sense a failing TOB ..:popcorn:

Originally Posted by Tcoat (Post 3026140)

Don't panic just yet. There are loads and loads of guys that have never had an issue. If it is going the tell tail sign is the squealing that you can change or stop by applying the clutch. Even though I knew what the issue was I waited too long after the squealing started and paid the price. It was the lack of the squeal (whine) in the first post here that originally had me thinking it wasn't the issue. Idk's follow up post however describes the final moments of mine almost word for word. The only thing he s missing is the burning smell and having to pull the pedal back up with his toes so maybe he hasn't totaled the clutch yet.



In hindsight I have little doubt that there are symptoms before the squeal starts but they are so gradual and unobtrusive that they are not noticed. They may not even be evident in an inspection but I am sure they are there. Ultramaroon has modified his clutch so it requires more pedal pressure. When I was driving his car he asked me what I thought and I said I liked it but really didn't feel a huge difference from my stock one. Once my car was fixed and I pushed the clutch for the first time it was a night and day difference from his. I think that the bearing had slowly been seizing up and although it was not creating noise yet it did take more pedal pressure to operate it. It had just happened so gradually that I never noticed the increase so the pressure felt "normal" to me. Now I am not happy with the stock pedal pressure so either need to do his cylinder mod or hope the bearing seizes up a bit again.

Originally Posted by idkwhatimdoing (Post 3025950)

Damn rain makes this tin can sound like, well, a tin can.

Originally Posted by Ultramaroon (Post 3026166)

All that mechanical advantage of the stock setup not only makes for a vague clutch. It also makes it tougher to feel when the TOB starts binding on the quill.

Originally Posted by humfrz (Post 3026201)

I have a question.

Is there any way to "see" the TOB without taking the bell housing off .. ?? Is there any inspection holes or any way to get a small flexible scope in there .. ??

Related question; would it be possible to "hear" a TOB going bad (like with a stethoscope) before it starts screaming...??


humfrz

Originally Posted by ermax (Post 3026205)

I bet you could fit a scope in there. When you pull the dust cover back the opening is fairly big. Not sure you could spot a bad one with a scope though. When I replaced mine it didn’t visually look bad. It just didn’t spin freely anymore. If it looked like Tcoat’s, well that’s a different story. Hahaha.

Originally Posted by Ultramaroon (Post 3026233)

No brainstorming necessary. It gets hot and melts the center bushing before it frags. The question is how long it lasts in that time between failure and catastrophic failure.

Originally Posted by idkwhatimdoing (Post 3026241)

Haven’t had to lift the pedal up with my toe just yet... I expect such an inconvenience to happen on my 50 year old Camaro...
As for the burning smell I did notice what smelled like clutch burning when I got home after riding the freeway in 5th gear for about 15 miles🙄I use my footrest like a good boy.


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Originally Posted by guybo (Post 3026243)

You should hear the rain with a gutted rear seat and trunk. :suicide:

Does anyone know if the TOB is covered by the full warranty or the powertrain warranty? Is that considered a powertrain part?

Originally Posted by guybo (Post 3026243)

You should hear the rain with a gutted rear seat and trunk. :suicide:



Does anyone know if the TOB is covered by the full warranty or the powertrain warranty? Is that considered a powertrain part?

Originally Posted by ermax (Post 3026249)

There is a TSB for 2013-2016 now which says it’s covered.

Originally Posted by ermax (Post 3026249)

There is a TSB for 2013-2016 now which says it’s covered.

Originally Posted by Tcoat (Post 3026248)

That was probably how mine was for a while before it went totally bad. Did you notice any difference in pedal feel when you changed it?

Originally Posted by ermax (Post 3026292)

The improved feel is probably more the grease than the TOB.

Originally Posted by Ultramaroon (Post 3026338)

What did the quill look like. Was it all scored?

Originally Posted by ermax (Post 3026292)

Mine started with a screeching sound on a cold morning when lightly pressing the clutch. Presing farther on the pedal loaded it up enough for the sound to go away. Releasing it again and then lightly pressing would produce the screech again. But after driving for a few minutes it would heat up enough to clear up. It was obvious it was the TOB so I tackled it that weekend. The clutch pedal felt much better after replacing it but this is the case after almost any clutch service where you re-grease everything. The improved feel is probably more the grease than the TOB.

Originally Posted by Tcoat (Post 3026359)

You could be correct. In 40 years and 20 or so MTs I have only had to replace one clutch so have never experienced stock back to stock. Any other replacements I did I was changing the whole works to performance equipment so I expected the changes. This change was more significant that I would attribute to just new lube though. I could also be second guessing myself at this point and the change wasn't as big as it seems.

Originally Posted by ermax (Post 3026413)

Well looking at your photos I suspect a lot of your improvement was from the TOB actually sliding freely again. Mine was really fine other than not spinning well. I'm sure it was building up heat and at some point it would have melted like yours. I guess I lucked out and got the warning signs unlike with yours.

Originally Posted by idkwhatimdoing (Post 3026548)

Been doing some research, I think the lack of proper lubrication to the TOB (courtesy of Toyota) and the fact that there is no f-ing clutch fork return spring to keep the bearing from moving around on its own makes the perfect storm for this issue. Thoughts?


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