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DIY Fix: High-pitch Whine from Drive Unit(s)

Mash

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Nov 10, 2019
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So it's about passing noise from the motor and not really bad connection. Don't see how DIY of that is possible without a new cable purchase.
 

0ptions

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Feb 28, 2017
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So it's about passing noise from the motor and not really bad connection. Don't see how DIY of that is possible without a new cable purchase.
Perhaps. I don't think that is all it is. Note in the TSB, if the resistance is over a certain value, the tech has to elevate the issue to engineering. Perhaps the folks who have tightened their cables, got it within that resistance value by doing so.
 

Mash

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Nov 10, 2019
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Perhaps. I don't think that is all it is. Note in the TSB, if the resistance is over a certain value, the tech has to elevate the issue to engineering. Perhaps the folks who have tightened their cables, got it within that resistance value by doing so.
Or they just shifted it somewhat so it's vibrating less....
 
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camalaio

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May 28, 2019
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Or they just shifted it somewhat so it's vibrating less....

That's absolutely entirely possible. Keep in mind my post also mentioned one of the bolts was actually a bit loose, which doesn't help things (though that was the front drive unit).

With solid core wire, it'll almost certainly loosen from the ring terminal crimp over time. I don't mean "fall out", but potentially degraded contact. I'm finding it a bit hard to believe they ever thought solid core wire was good there, perhaps just hoping there wasn't enough vibration? It's not like I've worked on >1000 cars or something, but this strikes me as an odd choice. At least it maybe explains the root cause for some folks.

Mine was pretty clearly the stranded wire from my recollection. The pictures from the TSB show a completely different looking cable as well, and looks like neither the "F" nor "G" ground straps we've seen. As mentioned in the TSB, this might apply only to really really early production 3s.

Continuing the DIY theme but not actually recommending anything because I recommend that you don't, it's just a dumb ground strap. It's pretty easy to "fix", replace with something else (stranded wire...), etc.
 
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Sophias_dad

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I just did this work (for the rear only so far) because I was swapping to my winter rims/tires. I found that I could see and get a socket wrench on the drive unit's end of the ground strap(two 3/8" extensions, an adapter, one 1/4 extension, and a socket), but I was too chicken to remove it because it looked like it would be 'questionable' if I could reinstall it once I got it out. Instead I just tightened that one a bit, not that it was loose to start with.

The outer end I disconnected, hit both sides of the eye and the nut and the landing on the stud with a dremel driven wire brush, and to top it all off I carefully applied some nickel based anti-sieze(cause who doesn't have that laying around!) such that it only hit the contact spots and not the stud itself, hoping it would make an even better connection. Finally, the stud got a touch of blue loctite so the nut doesn't work loose. I could easily see applying a layer of something over top of the whole assembly someday to reduce corrosion, but maybe that'll wait for Spring.

Its raining cats and dogs right now, so I couldn't tell if it made a difference.

I'll be doing the front strap when I get around to doing the Teslaoffer frunk opener that's been sitting in my garage for a month.
 

KenC

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Sep 4, 2018
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In the other thread, I posted my experience tightening both straps. The rear was easy and braided wire, and made a noticeable difference, but didn't completely eliminate the whine. The front was harder, and a solid-wire, and made no difference to the sound. I did the rear first, waited a couple weeks then did the front. Overall, it's fairly easy, and well worth trying if a SC is not cooperating or far away, like it is for me.
 

KenC

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Sep 4, 2018
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So, I wanted to re-try tightening the rear ground strap. And guess what, it worked! I no longer have any whine! Thanks to @camalaio for trying this and posting it.

Just to recap, I had a whine from 38mph to 52mph, with two peaks at 38 and 48mph. I wanted to try tightening the rear strap first, then the front strap later, to see if I could help ID where the whine was coming from.

I removed the one end, the easily reachable one, from the rear braided ground strap. Takes no time at all after removing the rear driver-side tire. Cleaned it, and retightened. My whine improved, as the range was smaller, 41mph to 45mph, and now only a single peak around 42mph.

After a few weeks, I did the front, but the front solid ground strap was hard to reach, and so I only tightened it. The sound had no change. Interesting that it was the rear braided strap and not the front solid strap that made some difference.

Now, with the weather cold, I wasn't too interested in re-doing the rear strap, but today, the temps warmed up, and so I redid the rear strap, MUCH tighter and gave it a squirt of anti-corrosion spray for good measure. And guess what? The whine is completely gone! So, happy that this simple fix worked. Honestly, now that I've done it, I think it might only take 15mins. Lift your rear driver side tire, remove it, the strap nut is easily reachable, remove that, clean it, reattach MUCH tighter, and put the wheel back on. Honestly, it's little more than changing a tire. 15 to 20mins.

Thank you, camalaio!

I'm just annoyed I didn't fix this correctly the first time, but I read that TSB where it sounded like you shouldn't over tighten the nut. The steps first had you "hand-tighten" the nut. Then you tightened it to 10NM, which is not that tight. In the end, I tightened it considerably more tight. Maybe that's why some of us have the whine, 10NM is not tight enough?
 
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Mash

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Nov 10, 2019
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714
Prague
So, I wanted to re-try tightening the rear ground strap. And guess what, it worked! I no longer have any whine! Thanks to @camalaio for trying this and posting it.

Just to recap, I had a whine from 38mph to 52mph, with two peaks at 38 and 48mph. I wanted to try tightening the rear strap first, then the front strap later, to see if I could help ID where the whine was coming from.

I removed the one end, the easily reachable one, from the rear braided ground strap. Takes no time at all after removing the rear driver-side tire. Cleaned it, and retightened. My whine improved, as the range was smaller, 41mph to 45mph, and now only a single peak around 42mph.

After a few weeks, I did the front, but the front solid ground strap was hard to reach, and so I only tightened it. The sound had no change. Interesting that it was the rear braided strap and not the front solid strap that made some difference.

Now, with the weather cold, I wasn't too interested in re-doing the rear strap, but today, the temps warmed up, and so I redid the rear strap, MUCH tighter and gave it a squirt of anti-corrosion spray for good measure. And guess what? The whine is completely gone! So, happy that this simple fix worked. Honestly, now that I've done it, I think it might only take 15mins. Lift your rear driver side tire, remove it, the strap nut is easily reachable, remove that, clean it, reattach MUCH tighter, and put the wheel back on. Honestly, it's little more than changing a tire. 15 to 20mins.

Thank you, camalaio!

I'm just annoyed I didn't fix this correctly the first time, but I read that TSB where it sounded like you shouldn't over tighten the nut. The steps first had you "hand-tighten" the nut. Then you tightened it to 10NM, which is not that tight. In the end, I tightened it considerably more tight. Maybe that's why some of us have the whine, 10NM is not tight enough?
Their issue is there is a rust inside threads. So it's not about torque, it's about cleaning it and stopping rust to go in threads again.
 

KenC

Active Member
Sep 4, 2018
3,706
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Maine
Their issue is there is a rust inside threads. So it's not about torque, it's about cleaning it and stopping rust to go in threads again.
Interesting, maybe my issue was different, because there was no rust in the nut threads. Just didn't seem all that tight, and the specs say it should be tightened to 10NM or 7ft-lbs, which is not much more than finger-tight.
 

Sophias_dad

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Jul 29, 2018
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Massachusetts
Maybe that's why some of us have the whine, 10NM is not tight enough?

Lucky for me I read the TSB's torque spec only AFTER I tightened it as much as my calibrated arm/hand thought wise. Were I to estimate, I'd say it was around 30NM. I'm not sure I'm gonna check it(ever) because I suspect its very near the breaking point, and I presume if it breaks I'm super-screwed.
 
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