Grinding When Letting Off Clutch

[friedmud]

Just got my manual '19 GT Base with PP1, AE, Safe and Smart. Absolutely LOVE the car... but I am hearing a grinding/scraping sound when shifting at higher revs (+5k).

I showed my dealer the video below yesterday - they have contacted Ford about it.

Note: I have driven manuals for over 20 years (yes, I'm old, lol)... including another manual mustang. This is not happening while shifting - only when smoothly letting out the clutch.

Has anyone else experienced this? I've searched and found a couple of other similar threads - but haven't really seen any resolution (and it's not clear if they had the same issue).

Here is a video:

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[Deleted member 35644]

That's bizarre. A grind after you've already engaged the gear. Input shaft issue?

 

[friedmud]

That's bizarre. A grind after you've already engaged the gear. Input shaft issue?

Somehow good to hear that it's bizarre, lol - it certainly seems abnormal to me.

The tech at the dealer said that it may be corrosion on the clutch(es). This is a _new_ 2019 that has been on the lot for a while (maybe up to 2 years)... so it's possible. He told me to drive it and see if it gets better. I honestly can't argue with that logic since that's all I want to do anyway!

 

[friedmud]

BTW: I can certainly _feel_ this as well... more in the clutch... but I can also feel it in the stick.

If it were happening when switching gears I would say that it feels like a synchro issue... but that's not what's going on...

 

[Deleted member 35644]

I've experienced plenty of clutch & manual trans woes in my life. Squealing throw-out bearings, bad synchros, disintegrating pressure plates, etc. but I've never heard what sounds exactly like gear grind after a gear is already engaged and the clutch is being released. I hope your tech is right, and if he is, it'll be a first for me to hear a clutch causing that noise. Seems it would take a very rusty pressure plate and / or flywheel to make that noise, for this long. Good luck!

 

[Conman1138]

I get the exact same sound occasionally in my car, it has done it since I bought it two years ago. It only happens at high rpm shifts if I let the clutch out slowly and start to get on the gas while still letting the clutch out. I've adapted my driving style to avoid it.

To me, it sounds like something vibrating very loudly, like a metal bracket. I can sometimes get the sound on demand if I get RPM up and put some pressure on the clutch pedal. I have never had it diagnosed, and it hasn't had any effect on how the car drives. I'm very interested in finding out what your dealer determines, though!

 

[friedmud]

I get the exact same sound occasionally in my car, it has done it since I bought it two years ago. It only happens at high rpm shifts if I let the clutch out slowly and start to get on the gas while still letting the clutch out. I've adapted my driving style to avoid it.

To me, it sounds like something vibrating very loudly, like a metal bracket. I can sometimes get the sound on demand if I get RPM up and put some pressure on the clutch pedal. I have never had it diagnosed, and it hasn't had any effect on how the car drives. I'm very interested in finding out what your dealer determines, though!

Fascinating... I definitely don’t need to push the gas as I let out the clutch for it to happen - but that does seem to make it worse.

After more driving with it today it seems like the issue is somewhat related to the rev-hang this car has. I’m not intentionally trying to shift fast - but I am shifting faster than the RPMs are naturally coming down once I get off the throttle and push in the clutch. If you watch closely in the video you can see that the sound occurs just as the engine has to quickly spin down to match the revs of the new gear.

After experimenting, I don’t get the sound if I wait for the engine to completely spin down first. But - that’s like an eternity... I can feel the car decelerating the whole time...

So: one potential longer term fix is to get a tune that removes the rev-hang... but I certainly wouldn’t do anything that would mess with the warranty...

 

[Conman1138]

Fascinating... I definitely don’t need to push the gas as I let out the clutch for it to happen - but that does seem to make it worse.

After more driving with it today it seems like the issue is somewhat related to the rev-hang this car has. I’m not intentionally trying to shift fast - but I am shifting faster than the RPMs are naturally coming down once I get off the throttle and push in the clutch. If you watch closely in the video you can see that the sound occurs just as the engine has to quickly spin down to match the revs of the new gear.

After experimenting, I don’t get the sound if I wait for the engine to completely spin down first. But - that’s like an eternity... I can feel the car decelerating the whole time...

So: one potential longer term fix is to get a tune that removes the rev-hang... but I certainly wouldn’t do anything that would mess with the warranty...

My car has been tuned. I'll have to reach out to Lund and see if their standard tunes remove any rev hang, I would assume they do. But I do know that these cars have pretty heavy dual-mass flywheels, which greatly contributes to how long it takes for revs to come back down. It took me a long time to get used to shifting slowly with this car. Having to shift slowly to be smooth seems to be a common complaint with the 18+ manual cars, and it's especially important at high rpm on the stock clutch.

Based on your description, it seems like it's much easier to produce the sound in your car, but it's definitely the same thing I hear when the conditions are right.

 

[friedmud]

My car has been tuned. I'll have to reach out to Lund and see if their standard tunes remove any rev hang, I would assume they do. But I do know that these cars have pretty heavy dual-mass flywheels, which greatly contributes to how long it takes for revs to come back down. It took me a long time to get used to shifting slowly with this car. Having to shift slowly to be smooth seems to be a common complaint with the 18+ manual cars, and it's especially important at high rpm on the stock clutch.

Based on your description, it seems like it's much easier to produce the sound in your car, but it's definitely the same thing I hear when the conditions are right.

The rev-hang is usually more associated with the electronic throttle control leaving the throttle open a bit after you let off the gas so that the engine can burn any excess fuel for emissions purposes. It is something that should be able to be mostly removed with a tune.

I went for a drive today for lunch... and I have to admit that I'm starting to get a bit bummed about all of this. Any shift over about 5k RPMs is just no fun... I either have to hold it forever and slow down or hear this noise.

Note that I'm not even revving hard or to redline yet... still letting it go through a break-in period (manual recommends 1k miles). I can't imagine how much worse this is going to be once I'm actually getting on it...

Hope I hear from the dealer soon...

 

[Conman1138]

The rev-hang is usually more associated with the electronic throttle control leaving the throttle open a bit after you let off the gas so that the engine can burn any excess fuel for emissions purposes. It is something that should be able to be mostly removed with a tune.

I went for a drive today for lunch... and I have to admit that I'm starting to get a bit bummed about all of this. Any shift over about 5k RPMs is just no fun... I either have to hold it forever and slow down or hear this noise.

Note that I'm not even revving hard or to redline yet... still letting it go through a break-in period (manual recommends 1k miles). I can't imagine how much worse this is going to be once I'm actually getting on it...

Hope I hear from the dealer soon...

Correct, but removing rev hang with a tune can only do so much when you have a heavy flywheel, it'll still take time for RPM to drop. These cars will also "pause" rpm drop for a second when it reaches matching rpm for the next gear up, my car still does this even with a tune. Either way, I don't believe rev-hang is the issue.

I'm really hoping your dealer can shed some light on this, because I've been curious about this noise for a while.

Don't let it bum you out too much, these cars make a lot of concerning noises that don't actually indicate problems (i.e. 2k rattle, BBQ tick, driveline clacking). It could be as simple as some bracket vibrating loudly and not some major problem. Like I've said, my car has made this noise for 2 years, and it hasn't gotten any worse or caused any issues.

Fingers crossed for you!

 

[Elp_jc]

I've read about this exact issue before (don't remember the thread name back then), and the consensus was that it was 'normal', meaning basically all manual cars do it under the 'right' circumstances... which are if you shift quick enough not to allow the engine to drop to the next gear's rpm, and getting on the gas even a little before clutch pedal is out, which the OP already figured out. And yes, he was shifting a lot quicker than the tranny likes... but at a very acceptable speed IMO. This stupid tranny just doesn't like to be shifted with ANY gas at all, at any rpm. Hey OP, did you try shifting at your same speed, but without any gas, to see if it happens??? If not, give it a try; it might work. I just learned to shift without any gas, to be able to shift as smooth as possible on this thing. It's the trickiest manual to drive smoothly, and I've owned a lot of manual cars in my life.

A couple of points I want to make. First, rev hang has nothing to do with the (DBW) throttle; it's a combination of the dual-mass flywheel, and tuning dictated by the EPA. Second, don't confuse rev-hang with rev-matching, but in the OP's case, that wasn't the issue. With rev-match on, it also works on up-shifts... but as the OP alluded, after the true rev-hang allows the engine to finally drop, it stops again right where the next gear will be for another moment, and that's the rev-matching. And that is what the tranny likes best . But yes, you need to drive like a senile grandpa, which sometimes is just not possible.

I haven't experienced that noise, but I'm sure my car would do it if provoked. And that's why I think the OP will find that releasing the clutch without gas might slow his shifts a little, but they'd probably be quicker than letting the engine drop to the next gear. Curious to hear about that test .

 

[ice445]

Ford performance kit/tune removes the rev hang and keeps some of the warranty.

My car had a problem for a while where it would rev hang and then stop at the wrong RPM for the next gear, randomly. Trying to shift resulted in a strong buck like you were dumping the clutch standing still, lol. Ended up tearing one of my diff bushings when it did that. Ever since my last oil change at the dealer it has stopped doing it (maybe they updated software). Now the revs only hang if you floor it and then let off and don't shift. Not sure how helpful that is but there is hope.

As far as the sound, sounds like a defect in the clutch itself. Maybe the portion where it rides in the input shaft of the transmission.

 

[friedmud]

I've read about this exact issue before (don't remember the thread name back then), and the consensus was that it was 'normal', meaning basically all manual cars do it under the 'right' circumstances... which are if you shift quick enough not to allow the engine to drop to the next gear's rpm, and getting on the gas even a little before clutch pedal is out, which the OP already figured out. And yes, he was shifting a lot quicker than the tranny likes... but at a very acceptable speed IMO. This stupid tranny just doesn't like to be shifted with ANY gas at all, at any rpm. Hey OP, did you try shifting at your same speed, but without any gas, to see if it happens??? If not, give it a try; it might work. I just learned to shift without any gas, to be able to shift as smooth as possible on this thing. It's the trickiest manual to drive smoothly, and I've owned a lot of manual cars in my life.

A couple of points I want to make. First, rev hang has nothing to do with the (DBW) throttle; it's a combination of the dual-mass flywheel, and tuning dictated by the EPA. Second, don't confuse rev-hang with rev-matching, but in the OP's case, that wasn't the issue. With rev-match on, it also works on up-shifts... but as the OP alluded, after the true rev-hang allows the engine to finally drop, it stops again right where the next gear will be for another moment, and that's the rev-matching. And that is what the tranny likes best . But yes, you need to drive like a senile grandpa, which sometimes is just not possible.

I haven't experienced that noise, but I'm sure my car would do it if provoked. And that's why I think the OP will find that releasing the clutch without gas might slow his shifts a little, but they'd probably be quicker than letting the engine drop to the next gear. Curious to hear about that test .

In the video I'm shifting without any throttle input at all. I have attempted to get off the throttle even earlier to help induce a slowdown in the engine... it doesn't make a difference.

Engineering Explained did a great video on rev-hang last year:

Agreed on rev-matching... I'm _loving_ that feature. Makes those downshifts smooth and quick - not too mention making an awesome sound as I blip down through the gears at a light. Seriously cool.

I do also like the feature that it will hold the RPM at the correct spot for upshifts (if you wait long enough for the engine to slow down). That is cool - and helpful.

I have to believe that this sound/grind is not normal. I've never heard/felt anything like it in any other car - even in any other mustang (I've ripped through the gears in my dad's '13 many times). If you have to drive it like a grandma... then what's the point?

One more thing: I've watched 1000 youtube reviews of this car - and every single one of them does either a drag-off with another car or at least a dash from 0-100, etc. There is no way they are all shifting slowly. I have to wait something like 3-4 seconds for the engine to spin down completely to avoid this sound...

 

[friedmud]

Ford performance kit/tune removes the rev hang and keeps some of the warranty.

My car had a problem for a while where it would rev hang and then stop at the wrong RPM for the next gear, randomly. Trying to shift resulted in a strong buck like you were dumping the clutch standing still, lol. Ended up tearing one of my diff bushings when it did that. Ever since my last oil change at the dealer it has stopped doing it (maybe they updated software). Now the revs only hang if you floor it and then let off and don't shift. Not sure how helpful that is but there is hope.

As far as the sound, sounds like a defect in the clutch itself. Maybe the portion where it rides in the input shaft of the transmission.

Thanks - I have been thinking about the Ford Performance Tune... and I've read similar anecdotes that say that it helps with rev-hang. I will probably end up doing that no matter what happens here.

Another poster said it may be something with the input shaft. I'll try to pass that along. Thanks!

I still haven't heard from my dealer...

 

[Conman1138]

Thanks - I have been thinking about the Ford Performance Tune... and I've read similar anecdotes that say that it helps with rev-hang. I will probably end up doing that no matter what happens here.

Another poster said it may be something with the input shaft. I'll try to pass that along. Thanks!

I still haven't heard from my dealer...

Another thought that I've had is that the noise might be a characteristic of the twin-disc clutch in the 18+ MT-82 cars. I know that aftermarket twin-disc setups can introduce noises where the intermediate disc can chatter when disengaged or partially engaged. OEM solutions are supposed to mitigate noises like this, but you can't expect anything perfect from Ford...

Maybe you just have a particularly noisy clutch, especially since you are still in the break-in period. If what you're experiencing falls outside of "normal", a warrantied clutch assembly replacement might do the trick.

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