High pitched noise from drive unit
High pitched noise from drive unit
Hi all,
I'm posting this here hoping you all may be able to shed some light on what this noise is. At the moment, our best guess is the front drive unit/a bad or faulty bearing design.
There is a large number of Tesla Model Y and 3 owners that have been vocalizing their concerns and frustrations with this noise. There is a very long thread over on Tesla Motors Club forums where you can read all about it. I don't know what the policy is for posting links to other forum boards, so I'll refrain from posting the link to it for now. The noise we are hearing, which can not be heard by everyone (frequency), is the noise heard (if you can hear it) in this video:
This noise is seemingly only present in cold weather (50 degrees fahrenheit or colder), above a certain speed (50mph). Although, some have heard it at lower speeds. It is even being heard on the new Model 3 Highland models.
Does anyone know what this noise is and/or how one might eliminate it? Tesla service centers have replaced front drive units over this noise, with some replacements solving the problem, but most failing to solve it. Tesla has taken a different stance on these drive unit swaps recently, and is now stating that although the noise is known to Tesla engineering, it is not something they are being authorized to perform a repair for.
I'm posting this here hoping you all may be able to shed some light on what this noise is. At the moment, our best guess is the front drive unit/a bad or faulty bearing design.
There is a large number of Tesla Model Y and 3 owners that have been vocalizing their concerns and frustrations with this noise. There is a very long thread over on Tesla Motors Club forums where you can read all about it. I don't know what the policy is for posting links to other forum boards, so I'll refrain from posting the link to it for now. The noise we are hearing, which can not be heard by everyone (frequency), is the noise heard (if you can hear it) in this video:
This noise is seemingly only present in cold weather (50 degrees fahrenheit or colder), above a certain speed (50mph). Although, some have heard it at lower speeds. It is even being heard on the new Model 3 Highland models.
Does anyone know what this noise is and/or how one might eliminate it? Tesla service centers have replaced front drive units over this noise, with some replacements solving the problem, but most failing to solve it. Tesla has taken a different stance on these drive unit swaps recently, and is now stating that although the noise is known to Tesla engineering, it is not something they are being authorized to perform a repair for.
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Re: High pitched noise from drive unit
It sounds to me like its something rubbing. The way it cuts out over bumps makes me wonder if maybe there's either something rubbing against an axle or an issue in a CV joint. I'd take a look around the front suspension area and see if there's any witness marks.
The other alternative (i.e. not a mechanical issue) is that it is related to the switching frequency in the inverter, in which case there's really nothing to be done. I think that's less likely but its possible.
The other alternative (i.e. not a mechanical issue) is that it is related to the switching frequency in the inverter, in which case there's really nothing to be done. I think that's less likely but its possible.
If at first you don't succeed, buy a bigger hammer.
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
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1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
Re: High pitched noise from drive unit
I do not believe it is suspension-related, unfortunately. Tesla SCs have been confirming that the noise we are all hearing is coming from the front drive unit. Those statements are being made (in multiple service orders, on multiple vehicles - Y and 3) after these SCs have had our vehicles for multiple days. No one (there are a lot of us) has been able to solve for this noise except for a very few edge cases (from awhile ago) where SCs were replacing the front drive units. Some of those replacements led to the noise being eliminated, some the noise becoming fainter and some, no change whatsoever. Now Tesla refuses to replace the front drive units. Frustrating noise to deal with - I wish I was lucky enough to not to hear it.
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Re: High pitched noise from drive unit
Ok, follow up question - does the sound change pitch relative to speed? You note that most hear it above 50mph, but does it change as the speed varies?
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1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
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Re: High pitched noise from drive unit
From the video linked above, took the audio, loaded it into Audacity (a really nice free audio processing tool), and see a quite stable tone at around 11kHz. Personally I cannot hear it, but it is clearly there. The frequency is stable, and the tone has some gaps. Would have been nice to see the speedometer at the video instead of the jeans
I'd propose to place some microphones into the interesting places to find out the loudest spot.
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Re: High pitched noise from drive unit
That frequency seems to be almost the same as my tinnitus, had to really play with the volume to make sure I was hearing it.
If my car was doing that I would probably try to isolate it with an automotive stethoscope if possible. I'd be checking different parts of the drive unit as well as the wheel bearings, and anything metallic near the motor just in case it's being induced by the AC.
Sometimes manufacturers add mass to problematic parts, which will shift any harmonic frequencies up and hopefully out of the range of the human ear. The 2010 Chevrolet Camaro had terrible noise from its front brakes. For those models, the fix was to stick a bunch of lead wheel weights to the outside of the calipers. 2011+ models had a more professional-looking set of weights permanently affixed to the caliper. I wonder if something like that would help here? I feel like if I was being driven sufficiently insane by the noise and couldn't isolate it, I'd be sticking weights to various parts just to see if it helped.
If my car was doing that I would probably try to isolate it with an automotive stethoscope if possible. I'd be checking different parts of the drive unit as well as the wheel bearings, and anything metallic near the motor just in case it's being induced by the AC.
Sometimes manufacturers add mass to problematic parts, which will shift any harmonic frequencies up and hopefully out of the range of the human ear. The 2010 Chevrolet Camaro had terrible noise from its front brakes. For those models, the fix was to stick a bunch of lead wheel weights to the outside of the calipers. 2011+ models had a more professional-looking set of weights permanently affixed to the caliper. I wonder if something like that would help here? I feel like if I was being driven sufficiently insane by the noise and couldn't isolate it, I'd be sticking weights to various parts just to see if it helped.
Re: High pitched noise from drive unit
Sorry about the video; it isn't mine; I snagged it from the 40-page thread about this issue on the other forum board. I added a few more sound clips below for reference.
Does the sound change pitch relative to speed?
It does not.
In November of 2022, a user on the other forum stated.
"I had mine resolved. They diagnosed it as a burnt out bearing in the front motor and they replaced the front drive unit."
As I mentioned earlier - some folks (very few) have had this noise solved by Tesla replacing their car's FDU. The cases of this that I've found were all in early 2023 or earlier. Now Tesla will not replace the FDU for this noise. A lot of us believe that this is a bearing issue (Tesla may have switched bearing suppliers or design at some point?), but we don't know how to prove it. I think it sounds oddly similar to the noise heard here... but I could be wrong.
"I recorded the sound and punched up the high frequencies to make it easier to hear."
"It's a high frequency noise that sounds sort of like crickets or hissing that appears when it's <70 degrees out, and you're driving >50 mph. Coming from the front drive unit. According to one service center, it's a bad bearing. You can hear the noise cut in and out at about 13s in the recording. It can come and go like that, even at speed."
Does the sound change pitch relative to speed?
It does not.
In November of 2022, a user on the other forum stated.
"I had mine resolved. They diagnosed it as a burnt out bearing in the front motor and they replaced the front drive unit."
As I mentioned earlier - some folks (very few) have had this noise solved by Tesla replacing their car's FDU. The cases of this that I've found were all in early 2023 or earlier. Now Tesla will not replace the FDU for this noise. A lot of us believe that this is a bearing issue (Tesla may have switched bearing suppliers or design at some point?), but we don't know how to prove it. I think it sounds oddly similar to the noise heard here... but I could be wrong.
"I recorded the sound and punched up the high frequencies to make it easier to hear."
"It's a high frequency noise that sounds sort of like crickets or hissing that appears when it's <70 degrees out, and you're driving >50 mph. Coming from the front drive unit. According to one service center, it's a bad bearing. You can hear the noise cut in and out at about 13s in the recording. It can come and go like that, even at speed."
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Re: High pitched noise from drive unit
Given that it doesn't change frequency with speed, I am very skeptical that it is caused by any rotating components such as a bearing. In my opinion, that points to the inverter itself and likely its switching frequency. That could also explain Tesla's refusal to replace the units. Likely, they initially assumed it was a bearing issue like the LDUs had, but upon examination determined its an inverter noise issue.
If at first you don't succeed, buy a bigger hammer.
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
Re: High pitched noise from drive unit
When the temperature gets warmer out, the noise completely goes away. Would this happen if it was the inverter/its switching frequency? The temperature being a variable is why we believe it may be bearing related. Colder temperatures impact lubricant viscosity, and metal will shrink or contract.P.S.Mangelsdorf wrote: ↑Fri Apr 05, 2024 12:05 pm Given that it doesn't change frequency with speed, I am very skeptical that it is caused by any rotating components such as a bearing. In my opinion, that points to the inverter itself and likely its switching frequency. That could also explain Tesla's refusal to replace the units. Likely, they initially assumed it was a bearing issue like the LDUs had, but upon examination determined its an inverter noise issue.
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Re: High pitched noise from drive unit
Hi all,
Furthermore, the noise completely vanishes after a supercharge.
And it’s audible only during cruising (when the FDU is idle).
Furthermore, the noise completely vanishes after a supercharge.
And it’s audible only during cruising (when the FDU is idle).
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Re: High pitched noise from drive unit
Does it come back as SOC decreases, or does it only come back after a Level 1/2 charge?
That's interesting.Dadaaaaaaa wrote: ↑Fri Apr 05, 2024 11:09 pm And it’s audible only during cruising (when the FDU is idle).
Does everyone who has this issue agree that it is coming from the front of the car? Is anyone hearing it coming from the rear and/or back seat area?
If at first you don't succeed, buy a bigger hammer.
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
Re: High pitched noise from drive unit
Yes, I would say that at this point, we all agree that it is coming from the front of the vehicle, not the rear.
Here is the thread on the other forum is you want to read through all forty pages.![Crying or Very Sad :cry:](./images/smilies/icon_cry.png)
Here is the thread on the other forum is you want to read through all forty pages.
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Re: High pitched noise from drive unit
No, the noise only reappears when the car cools down after being parked for a while. During long trips, the noise does’t return between supercharges.P.S.Mangelsdorf wrote: ↑Mon Apr 08, 2024 12:51 pm Does it come back as SOC decreases, or does it only come back after a Level 1/2 charge?
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Re: High pitched noise from drive unit
That, combined with the frequency not varying with speed, indicates to me that this is not coming from the drive unit. It's coming from some other system, likely cooling. Could be a pump, could be a valve, could be a fan. I'd lean towards valve.Dadaaaaaaa wrote: ↑Mon Apr 08, 2024 8:47 pm No, the noise only reappears when the car cools down after being parked for a while. During long trips, the noise does’t return between supercharges.
If at first you don't succeed, buy a bigger hammer.
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
1940 Chevrolet w/ Tesla LDU - "Shocking Chevy" - Completed 2023 Hot Rod Drag Week
https://www.youtube.com/@MangelsdorfSpeed
Re: High pitched noise from drive unit
Could anyone help me as I believe I have the same issue and driving home tonight my head is killing me with a high-pitched ringing? Had to take paracetamol as it's driving me mad. It was about 10 degrees outside and I get this noise on the 30-minute drive home that lasts for hours once I get home. I've had it in an SC about 5 times but as they can't hear the frequency OR by the time I drive it 1 hour to the SC it does not do it again they are reluctant to do anything. They say they've done the ground strap and the perimeter seal looks fine.
What can anyone suggest next? What are my options? Was thinking about a mobile engineer to try it?
https://youtube.com/shorts/jc5V-ZiKPgs
What can anyone suggest next? What are my options? Was thinking about a mobile engineer to try it?
https://youtube.com/shorts/jc5V-ZiKPgs
Re: High pitched noise from drive unit
Here is yet another example of a FDU replacement solving the problem...
https://www.evchargerreviews.net/my-tes ... irst-year/
Repair #5 for this owner.
https://www.evchargerreviews.net/my-tes ... irst-year/
Repair #5 for this owner.
Re: High pitched noise from drive unit
I came over from the Teslamotorclub forum to see what the thoughts were about the issue here. I have read and kept up with the 799-post-thread over there, as I am also experiencing the issue.
I also have a hard time believing it’s a bearing based on the fact the frequency is consistent. While there are quite a few people who have had the problem remedied by replacing the front drive unit, yes… most of those fixes required multiple FDU replacements to solve the issue. This means either, there are that many effected units OR the act of a dropping and replacing an FDU has an affect on whatever is causing this issue. I’m leaning towards the latter.
I’m still of the mindset that this noise is harmonic in nature. While I’m not at all familiar with inverters and the noises they produce, but I’m very familiar with mechanical issues. The best way I can explain this sound is as if it’s something not properly tightened that is excited by mechanical resonance. In this case, I suppose it’s even possible the noise could be trigged by a specific speed of the motor due to the magnetic impulses causing something immediately near the FDU to resonate? I’m thinking of how old transformer hum after the insulation materials start to degrade - the process that creates the sound being similar I mean..?
Furthermore, if it were a failing bearing, the noise would be increasing in volume over use. This doesn’t appear to the case. I haven’t seen one case of an FDU failure in which the noise was apparent prior to the failure.
Forgive me if I’m stretching definitions here or using the wrong words - I have no formal training in electrical or mechanical engineering.
*****
For those interested, the user ev_go123, over on Teslamotorclub, took a recording with a microphone attached to the FDU. While this does not necessarily mean the noise is coming from inside the FDU, it may be helpful to differentiate it from noises that could be coming from the inverters.
I also have a hard time believing it’s a bearing based on the fact the frequency is consistent. While there are quite a few people who have had the problem remedied by replacing the front drive unit, yes… most of those fixes required multiple FDU replacements to solve the issue. This means either, there are that many effected units OR the act of a dropping and replacing an FDU has an affect on whatever is causing this issue. I’m leaning towards the latter.
I’m still of the mindset that this noise is harmonic in nature. While I’m not at all familiar with inverters and the noises they produce, but I’m very familiar with mechanical issues. The best way I can explain this sound is as if it’s something not properly tightened that is excited by mechanical resonance. In this case, I suppose it’s even possible the noise could be trigged by a specific speed of the motor due to the magnetic impulses causing something immediately near the FDU to resonate? I’m thinking of how old transformer hum after the insulation materials start to degrade - the process that creates the sound being similar I mean..?
Furthermore, if it were a failing bearing, the noise would be increasing in volume over use. This doesn’t appear to the case. I haven’t seen one case of an FDU failure in which the noise was apparent prior to the failure.
Forgive me if I’m stretching definitions here or using the wrong words - I have no formal training in electrical or mechanical engineering.
*****
For those interested, the user ev_go123, over on Teslamotorclub, took a recording with a microphone attached to the FDU. While this does not necessarily mean the noise is coming from inside the FDU, it may be helpful to differentiate it from noises that could be coming from the inverters.
Re: High pitched noise from drive unit
I had the same issue with my M3P and after several visits to the SC with no luck I had to get a mobile engineer to visit my house and he diagnosed it as the rear motor. Got booked in and they changed it. Weather is better at the minute with higher temperatures so not 100% sure if it is cured yet. Took it out the other day and I thought I heard the hiss again. I do hope that they changed the correct drive unit? They had said they took it out with the front disabled and said it was without question the rear.