High pitched noise from drive unit

[Siciliano]

I'm very happy to revive this thread - after a few weeks of waiting, the Paramus NJ SC has approved my visit, and without even seeing my car they have ordered BOTH the front AND rear ground straps, and will replace both covered under warranty!

THANK YOU @Dante and @camalaio and others for all the very helpful info! Without you guys we never would have known the exact root cause of the issue and/or the necessary part numbers. It's exciting to know that this forum has directly helped to make a difference in the real world

I literally told the techs that "numerous people on the TMC forum had this exact issue and it was fixed by replacing the ground strap"...based on that info alone they have amazingly not only acknowledged the problem, but have ordered the parts and have agreed to fix it sight unseen. It has taken a few weeks, but I'm very happy with the outcome.

I copied this from the service estimate. The appt is finally scheduled for 10/19! I'm not sure why it says "correction"...I think it's because my previous service estimate listed that they would only diagnose the motor whine...


Correction: Ground Strap Front Drive Unit (Remove & Replace)

Parts Replaced or Added

Part

ASY,CABLE,FDU GND STRAP, M3(1070978-00-D)

Quantity

1.0

Correction: Ground Strap - Rear Drive Unit (Remove & Replace)

Parts Replaced or Added

Part

ASY,CABLE,RDU GND STRAP,M3(1070979-00-G)

 

[KenC]

Interesting that they're replacing both straps; has anyone else had them replace both, I thought it was only the rear one that was the issue?

 

[marcn]

Wow - it's great to hear that Tesla is starting to address this issue! I was waiting to hear more "success" stories like this before attempting to book a service appointment. It might actually be time to try.

Interesting that they're replacing both straps; has anyone else had them replace both, I thought it was only the rear one that was the issue?

I haven't had mine replaced/fixed (yet) but the sound is primarily coming from the front for me. I'll request both be changed in the service request though.

On a related note, here's a recent video of someone with this problem who will be attempting to get it fixed by Tesla. I'll be keeping an eye on this:

 

[0ptions]

I'm very happy to revive this thread - after a few weeks of waiting, the Paramus NJ SC has approved my visit, and without even seeing my car they have ordered BOTH the front AND rear ground straps, and will replace both covered under warranty!

THANK YOU @Dante and @camalaio and others for all the very helpful info! Without you guys we never would have known the exact root cause of the issue and/or the necessary part numbers. It's exciting to know that this forum has directly helped to make a difference in the real world

I literally told the techs that "numerous people on the TMC forum had this exact issue and it was fixed by replacing the ground strap"...based on that info alone they have amazingly not only acknowledged the problem, but have ordered the parts and have agreed to fix it sight unseen. It has taken a few weeks, but I'm very happy with the outcome.

I copied this from the service estimate. The appt is finally scheduled for 10/19! I'm not sure why it says "correction"...I think it's because my previous service estimate listed that they would only diagnose the motor whine...


Correction: Ground Strap Front Drive Unit (Remove & Replace)

Parts Replaced or Added

Part

ASY,CABLE,FDU GND STRAP, M3(1070978-00-D)

Quantity

1.0

Correction: Ground Strap - Rear Drive Unit (Remove & Replace)

Parts Replaced or Added

Part

ASY,CABLE,RDU GND STRAP,M3(1070979-00-G)

I like to think I played a role too...

 

[KenC]

So, thanks to everyone who contributed to this thread. Anyhow, I rotated my tires, and while the driver-side rear tire was off, I could see the ground strap, so I removed it, cleaned it, and reattached. While there, I used my leaf blower and blasted any loose debris in the under tray, etc.

It's only been a couple days, since I did it, but I used to get a double-peak whine between 38mph and 52mph, with peaks at 38mph and 48mph. Now, I have one soft, lower-pitch whine at 42mph that I strain to hear. Why? I have no idea.

I'll drive it for a week or so, to see if it changes or if I imagined the whole thing, before I consider re-doing the front strap attachment.

I'm wondering if I should have coated it with that battery terminal anti-corrosion gel. Thoughts?

 

[john5520]

I'm wondering if I should have coated it with that battery terminal anti-corrosion gel. Thoughts?

Sounds like a good idea. Don't really see a downside to it.

 

[Mash]

Sounds like a good idea. Don't really see a downside to it.

It adds resistance. Not too big to overheat contacts of battery, but enough to have bad grounding that contributes to that whine.

 

[KenC]

It adds resistance. Not too big to overheat contacts of battery, but enough to have bad grounding that contributes to that whine.

Interesting, is there any other kind of contact gel that reduces resistance, and that would reduce possible whine?

I was thinking reducing corrosion, would lower the risk of reduced resistance and possible whine, but don't want to do the opposite!

 

[john5520]

It adds resistance. Not too big to overheat contacts of battery, but enough to have bad grounding that contributes to that whine.

Well, I figured if it was good enough for a car battery ground strap, it should be OK for this application. First I've heard of this, interesting.

 

[Mash]

Well, I figured if it was good enough for a car battery ground strap, it should be OK for this application. First I've heard of this, interesting.

Whine could be the result of circuitry unable to release whole charge completely to the ground between the cycles. Oxidation certainly going to make that resistance too high, so stopping it helps. But connection should be designed to prevent oxidation happening in the first place without any coatings. If it's not - it's a warranty case. Any high metal content paste is anyway going to be worse than clean metal surfaces hard pressed into each other. Even for car battery it's just a stupid band-aid and instead you should have clean flat surface and tight fit of contacts.

 

[Tony_YYZ]

Hi All, OP here,

I booked a service appointment at the local Service Center to get this issue looked at again. I referenced TSB SB-18-17-003 (https://www.tsbsearch.com/Tesla/SB-18-17-003) which addresses a high motor noise level in the cabin by swapping out the rear ground strap with a revised unit.

I got back home from my appointment earlier today. I rode with the technician to have him hear the problem and he did acknowledge it. He also uttered the famous “within spec” words during our drive. I had to basically plead with him a bit about how it has gotten worse over time, it makes the driving experience unpleasant, etc. He finally agreed to take in into the service bay and check out the ground strap.

I waited there for about 1.5 hours while they took a look. When the technician was done he came back to me and said he removed the existing ground strap and cleaned up the mounting points from dirt and corrosion. He then said he took it for a test drive and that it was “night and day different”. I thanked him for taking the time to correct it, got my keycard and I was out of there. During the drive home it was DEFINITELY much more improved. The noise is still there ever so slightly but it’s at the point where if I’m not actively paying attention to it, I can’t hear it.

I do still wonder if they had actually replaced the ground strap with the revised part if that would have solved the issue 100%. But unfortunately with the way Tesla service has been heading for the past year or more, they are incredibly hesitant to replace parts unless absolutely required. So I do wonder if over time and changing of the seasons if the ground mount points will get dirty and corroded again and the noise will return. Time will tell.

 

[phigment]

Hi All, OP here,

I booked a service appointment at the local Service Center to get this issue looked at again. I referenced TSB SB-18-17-003 (https://www.tsbsearch.com/Tesla/SB-18-17-003) which addresses a high motor noise level in the cabin by swapping out the rear ground strap with a revised unit.

I got back home from my appointment earlier today. I rode with the technician to have him hear the problem and he did acknowledge it. He also uttered the famous “within spec” words during our drive. I had to basically plead with him a bit about how it has gotten worse over time, it makes the driving experience unpleasant, etc. He finally agreed to take in into the service bay and check out the ground strap.

I waited there for about 1.5 hours while they took a look. When the technician was done he came back to me and said he removed the existing ground strap and cleaned up the mounting points from dirt and corrosion. He then said he took it for a test drive and that it was “night and day different”. I thanked him for taking the time to correct it, got my keycard and I was out of there. During the drive home it was DEFINITELY much more improved. The noise is still there ever so slightly but it’s at the point where if I’m not actively paying attention to it, I can’t hear it.

I do still wonder if they had actually replaced the ground strap with the revised part if that would have solved the issue 100%. But unfortunately with the way Tesla service has been heading for the past year or more, they are incredibly hesitant to replace parts unless absolutely required. So I do wonder if over time and changing of the seasons if the ground mount points will get dirty and corroded again and the noise will return. Time will tell.

I don't think replacement is a 100% fix. They did replace mine and while improved, the noise is still there.

 

[Tony_YYZ]

I don't think replacement is a 100% fix. They did replace mine and while improved, the noise is still there.

Unfortunately I think the sound is a byproduct of using the Permanent Magnet motor. The intensity of it is at least affected by the grounding strap, possibly other points as well which I'm not familiar with.

I know Raven S and X owners have also been complaining about this with their PM motors. It's unfortunate that Tesla's hard line stance on this is that it's normal.

 

[KenC]

So, a couple weeks ago, I rotated my wheels and removed/cleaned the rear ground strap. After cleaning, the whine was better, where before the whine went from 38 to 52mph, with dual peaks at 38 and 48mph; now the range is from 40 to 45mph, with a single peak at around 42mph. I strain to hear it, but it's still there.

After enough time had passed, I decided to remove and clean the front ground strap. I undid the 10mm hex bolts holding the fabric front undertray on; got the face full of dust/dirt, cleaned that, and realized the ground strap was quite a reach. Anyway, I found it difficult to remove the strap, so I just tightened it a little. Turns out the front ground strap is solid, and not braided. Unfortunately, the sound has not changed at all since tightening the front strap.

While digging around under the car, I noticed that the "boots" around the front half shafts, connected to the motor, are quite rusty. Anyone else notice this, and would you consider it normal?

 

[KenC]

Unfortunately I think the sound is a byproduct of using the Permanent Magnet motor. The intensity of it is at least affected by the grounding strap, possibly other points as well which I'm not familiar with.

I know Raven S and X owners have also been complaining about this with their PM motors. It's unfortunate that Tesla's hard line stance on this is that it's normal.

So, is the solution to wait for Tesla to come up with a 2nd revised ground strap, then beg for them to replace the original; and if not, offer to pay them to have it replaced?

I mean what's the crux of the issue with the ground? Should the strap be a little thicker?

 

[john5520]

^^I would have the ground strap replaced with the revised version that already exists, then go from there.

 

[Tony_YYZ]

So, is the solution to wait for Tesla to come up with a 2nd revised ground strap, then beg for them to replace the original; and if not, offer to pay them to have it replaced?

I mean what's the crux of the issue with the ground? Should the strap be a little thicker?

The biggest issue is getting them to acknowledge it’s a problem. They love throwing around that “Within spec” term to people who complain about it but won’t ever show the “spec” to anyone.

Getting the strap replaced with the revised unit and having the mount points cleaned up would the best first step. After that, I’m really not sure what can be done. They don’t want to acknolwedge that it’s a real issue so they won’t be putting resources into fixing it.

 

[0ptions]

While digging around under the car, I noticed that the "boots" around the front half shafts, connected to the motor, are quite rusty. Anyone else notice this, and would you consider it normal?
View attachment 602748

Yes, that is normal. Other vehicles I've owned exhibited this. Typically it's the first thing to rust...

 

[SexyTessie]

Thanks for the informative thread. We have owned a 2018 Model 3 LR, RWD for only a few months now and I am brand new to the forum. Almost immediately after purchasing our car, we noticed the whining noise described here. After initially reading this thread a while back, we suggested the grounding screw/strap theory to a local technician. While he acknowledged the sound, he dismissed the theory because, once the car was placed on a hoist, we couldn't replicate the sound. So rather than just adjust the screws while the car was up in the air anyhow, he instead suggested the sound was due to our winter tires. I am not mechanically inclined, so my question is this: does the fact that the noise could not be reproduced when the car was on the hoist support the ground strap theory or not? Any feedback would be appreciated.

 

[john5520]

Thanks for the informative thread. We have owned a 2018 Model 3 LR, RWD for only a few months now and I am brand new to the forum. Almost immediately after purchasing our car, we noticed the whining noise described here. After initially reading this thread a while back, we suggested the grounding screw/strap theory to a local technician. While he acknowledged the sound, he dismissed the theory because, once the car was placed on a hoist, we couldn't replicate the sound. So rather than just adjust the screws while the car was up in the air anyhow, he instead suggested the sound was due to our winter tires. I am not mechanically inclined, so my question is this: does the fact that the noise could not be reproduced when the car was on the hoist support the ground strap theory or not? Any feedback would be appreciated.

That tech is what I'd call your typical dingbat! He should have just checked and tightened the screws. It would have been so easy for him to do. I was annoyed just reading that. I posted a TSB ealier in the thread which describes the noise as a vibration. Having the car on the hoist may not replicate the same forces the motor is subjected to when being driven on a roadway. But even if it did, what would it have taken for him to simply tighten the screws? If you do decide to take it back, print the TSB and have it on hand.