Crunching Noise When Decelerating In 2nd/3rd

[idkwhatimdoing]

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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[FirstWinter]

Video would be helpful in identifying the issue. Do me a favor and check underneath the car to see if possibly a cover/undertray has gotten loose and is dragging on the ground possibly.

[humfrz]

Originally Posted by idkwhatimdoing

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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Well, hello, idkwhatimdoing and welcome to ye ol forum .....

Good background information .....

OK, crunching noise ....... hmmmmm

* does it seem to be driveline related - does it do it with the clutch disengaged .. ??

* is it engine speed related .. ??

* does it increase or decrease with the car's speed - wheel/brake related ..??

* when the car is stationary, does the sound vary with whether or not the clutch is being pushed in (TOB).. ??

Come back ......

I'll summon @Tcoat and @Ultramaroon for you ....... Tcoat will tell you it's the TOB ....... Ultramaroon will tell you it's gear rollover.


humfrz

[Ultramaroon]

I'm not going to say anything until I hear a recording of the sound.

[Tcoat]

And I am not going to say TOB because once in gear it is fine. It is getting into gear where it is noisy.

[humfrz]

It's your move, here, @idkwhatimdoing .......


humfrz

[idkwhatimdoing]

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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[Tcoat]

Ummmmm That is the TOB!

[humfrz]

Originally Posted by idkwhatimdoing

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

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

[Tcoat]

Originally Posted by humfrz

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

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

The change is his description changed my armchair diagnosis.

[idkwhatimdoing]

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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[Tcoat]

Mine laughed all the way to the bank!


The fact you can make it come and go by pressing the clutch was the kicker.

[humfrz]

Originally Posted by idkwhatimdoing

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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Yep, the sound of rain on the roof of an FR-S reminds me of my childhood back on the farm. Sitting under a tin roof watching and listening to it rain ..... sipping on iced tea and chewing on a straw ......

Just relax, if it is a bad TOB, it will most likely hold together for another mile or two ......... (sorry,, bad joke) .....

Time fer ma oatmeal,, followed by a nap ZZZZZZZZZ

[idkwhatimdoing]

[QUOTE=Tcoat;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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