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Acceleration Shudder

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I had the same problem in November at around 8000 miles, vibration and low-pitched "growling" noise under heavy acceleration. The service center replaced both front halfshafts, but noted that the vibration was still present and escalated the matter to engineering. The vibration was much better, almost completely eliminated after the halfshafts were replaced, but now after about 2000 miles / 2 months it has gotten progressively worse and is about back to where it was prior to the halfshafts being replaced.
The first time I noticed the problem I had the original Michelin tires on T-Sportline 20" turbine wheels, this time I'm seeing it with the factory 20" wheels with Pirelli all-season tires, so I'm guessing that it's not related to the wheels or tires.
 
I noticed that there is now a "B" variant to the half-shafts, which usually signifies a revised part. Has anyone else had these installed?

"Parts Replaced or Added

Part Quantity
HALF SHAFT - FRONT LEFT (1027111-00-B) 1
HALF SHAFT - FRONT RIGHT (1027115-00- 1 B)"

Issue has been reduced in magnitude for me but has not disappeared entirely.
 
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I noticed that there is now a "B" variant to the half-shafts, which usually signifies a revised part. Has anyone else had these installed?

"Parts Replaced or Added

Part Quantity
HALF SHAFT - FRONT LEFT (1027111-00-B) 1
HALF SHAFT - FRONT RIGHT (1027115-00- 1 B)"

Issue has been reduced in magnitude for me but has not disappeared entirely.
Yes, I had them replaced September 27 with the numbers you listed. A key remark was that hard acceleration should only be done with the suspension in LOW position. Have you tried it in that position?
 
Yes, I had them replaced September 27 with the numbers you listed. A key remark was that hard acceleration should only be done with the suspension in LOW position. Have you tried it in that position?

Interesting....latest SW update ( 2.52.22 ) defaulted my setting to 'low" vs "standard". I was still able to change to speed varied when in park.

FWIW: I was advised that "low" setting will impact tire life so through this process Tesla is essentially cost shifting?
 
Yes. Much better in low. But if standard is really "standard" I'd prefer to be able to keep the suspension in that position and not be limited in my performance options.

Can understand not accelerating hard in high/v.high


Yes, I had them replaced September 27 with the numbers you listed. A key remark was that hard acceleration should only be done with the suspension in LOW position. Have you tried it in that position?
 
Oh gawd I hope they're not trying to spin this by now implying it's their recommended setting. I was told it's been escalated to eng because none of the sc's can figure it out.

I hope so. Have had this issue since day one. It is by far the most annoying issue about the car. A setting of Very Low with the B version half shafts results in zero shudder and super smooth acceleration. A step forward, but Low still results in a bit of shudder which is still unacceptable.
 
After FarmerDave’s comment about Low vs Standard I did some experimenting and it is definitely less pronounced in Low.
The shudder always happens on a particular road I drive with a curve up to the left and a speed change from 25mph to 50mph and a passing lane which I often take at >50mph. My car is in Standard to start and I had the auto-lower setting set to 70mph to avoid automatically changing up and down on country roads and spots just like this one. If is start out at Low (mind you I’m going 20-25 because of a sharp turn, bridge, and traffic at the bottom of the hill curve, the shudder only occurs when the car bounces up on its suspension (lumpy road, no business being in Low).
There is something most certainly wrong, it’s related to the suspension somehow but maybe not just the height but the design (uh oh). There is a wear component since I did not have It until 10k miles and it did not go away temporarily with fresh tires but as posters have noted changing out the half-shafts does not fix the problem. From another thread someone had success with adding a missing shear plate Slower acceleration and vibration/loose parts? in front motor
At one service visit they tried to recreate this with a test drive and reported it as nominal; I don’t imagine that they actually experienced what I experienced where it feels like something in the front is wearing and could fall off or break. I have another appointment tomorrow so we’ll approach the problem again and I’ll ask about shear plates (what are shear plates?)
 
I was told by the lead at the Tempe SC, that the problem was different lengths of the half shafts created a harmonic which is in phase at only one coincidental rotation of the two half shafts. At any other coincidental rotation the two are out of phase and you get the vibration, which could be dampened with larger bushings but that would harshen the ride. I'm not sure why increasing the mass of the shorter half shaft wouldn't equalize their frequencies, maybe it has to do with flex while spinning.
 
I had the same problem in November at around 8000 miles, vibration and low-pitched "growling" noise under heavy acceleration.

This is very helpful to know, because I started experiencing that too recently. Doesn't need to be heavy acceleration, though - just driving about 60 mph seems to make the car vibrate as if I'm on bumpy pavement. The growling/grinding, though, I only heard a couple of times, twice while accelerating fast and once in reverse out of my garage while in Low suspension.
 
Yes, I had them replaced September 27 with the numbers you listed. A key remark was that hard acceleration should only be done with the suspension in LOW position. Have you tried it in that position?

We got our car back yesterday from service and so far so good. In addition to the parts you both mention, I'm also seeing a jackshaft assembly replacement: JACKSHAFT ASSY, FR (1030632-00-A).

I'd forgotten how awesome this car was because of all the little issues we're seeing, but damnit when all things work as Elon envisioned, there's no other car that can return the same thrilling experience.
 
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Rev B part won't prevent a failure... Had both mine replaced at 7500 miles due to grinding noise and shudder on acceleration:

HALF SHAFT - FRONT RIGHT (1027115-00-B)
HALF SHAFT - FRONT LEFT (1027111-00-B)

Two weeks ago at 8500 miles, the right one failed completely with just mild acceleration and rendered the vehicle undriveable (loud clunk and extreme shudder with loss of steering - super dangerous and lucky I was able to get it safely stopped). Had to be towed to the service center and it's been under repair for the last two weeks due to other parts damaged in the process. Hoping to get it back soon and finally close out a Lemon Law buyback given my Model X is way over the days out of service limit and this failure was icing on the cake.

My only guess is that driving in a setting other than "low" will cause premature failure and the grinding noise with shudder is just a warning sign of impending failure.

You can hear the clunking as it's being pulled on to the flatbed:
 
Had the opportunity to pull a wood splitter 45 min down some not so great roads, speeds were 35 to 50mph (50 on the smooth parts). Because tow mode, the suspension was fixed in Standard. Because towing, acceleration was gentle. The vibration happened with any acceleration.

I had 4 other adults in the car for another trip yesterday down some similarly lumpy roads and they complained about the suspension. I moved the height from Low to Standard and even tried High which seemed to help a little but then they had to endure the vibration.

It not just hard acceleration at non-Low setting anymore but real world typical driving.
 
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Which service center did it? Do you have a part number for the jack shafts from the Repair Order? Thanks for the info. Still a problem on my car.

Received mine back a couple days ago with all new half shafts and jack shafts. Accelerates perfectly smooth now, even on my usual suspension setting (standard). We'll see how long it lasts. This is the second time the half shafts have been replaced, but the first time for the jack shafts.
 
Which service center did it? Do you have a part number for the jack shafts from the Repair Order? Thanks for the info. Still a problem on my car.
Indianapolis. I guess there's only one Jackshaft and two half shafts. I should really get under there and see how this thing works some day...

JACKSHAFT ASSY, FR (1030632-00-A)
HALF SHAFT - FRONT RIGHT (1027115-00- 1 B)
HALF SHAFT - FRONT LEFT (1027111-00-B)