Noise coming from front of the model x, underneath the front hood area during sudden acceleration

Noise coming from front of the model x, underneath the front hood area during sudden acceleration


I have a 2018 model x 75D with 10k miles on it.

Has anyone experienced the metal knocking sound coming from the front of the model x during sudden acceleration?

I almost feel that the electric front motor is unable to engage properly during sudden acceleration.

I don't hear anything during normal driving.

I took the model x to dealer and they replaced some part at front but the issue still there.

anyone had similar issue? Thanks.

jimglas | January 16, 2019

did your trunk monkey get locked in the frunk?

lilbean | January 16, 2019

Do you feel any vibration?

Vawlkus | January 16, 2019

Are you hearing this when going straight, or are you hearing it when accelerating into a turn?

jch | January 16, 2019

yes I feel light vibration from the "electric pedal" , this happens most of time when I make a right turn with hard acceleration, although yesterday when i was going straight, I floored the pedal and I heard the noise too.


mathwhiz | January 16, 2019

Yes. I describe it as a rattle coming from under the front floor (underfoot), and I'm guessing that this is a new symptom of the chronic front half-shafts problem, but I should know soon (service appt in about 2 weeks)...

Awhile back, Tesla updated the front half-shaft parts (to rev B) to overcome a 'front end shudder on acceleration, more likely on air suspension settings above LOW'. Many of us have had these parts replaced with the rev. B design, which seemed to resolve the problem. But, as I stated, I believe that this is just a new and less drastic symptom of a remaining problem with the new part... Only this symptom doesn't seem to be helped by keeping suspension on LOW. Once the B parts were installed, it seems that time eventually reveals the new problem...

I'll update after my appointment on 04-Feb.

mathwhiz | January 16, 2019

Oh and I agree, the problem is more easily demonstrated by accelerating out of a turn.

mathwhiz | January 16, 2019

Interesting that you (OP) described the sound as a "metal knocking sound". If what you mean is like the old ICE engine 'knocking' sound of incomplete combustion when they changed to unleaded gasoline in the late 70's, I agree. The sound is (oddly) quite similar.

jch | January 16, 2019

cool, thanks Mattwhiz. Please keep us updated. I will take the MX to service center once I hear from you.

Thanks again!

jch | January 16, 2019

and I agree, rattle sounds is more accurate.

markcohen | January 19, 2019

Interesting. I had a similar sound right after my annual service this week. I described it as a brief metal grinding or groaning sound while accelerating briskly. It did it 4-5 times in a row and I took the car back to the SC. Unfortunately it wouldn't do it when we test drove it but the SC took a look anyway. The only thing that they said that they found was that the bolts on a plastic door on the bottom of the car had not been fully tightened. The theory - unproven - was that maybe this door was fluttering in the wind at a particular speed/angle.

I do not believe that this was at all related to the half shaft issue which I previously had fixed and knock on wood seems to be fixed. At this point, I can't do anything else other than to keep listening in case it comes back.

MelaniaFromBrentwood | January 20, 2019

You have that tow hook in your Frunk. It’s that long metal bar with a loop at the end. You don’t have an engine so it’s sitting in the frunk and rattling around when you accelerate. Remove it. You’re welcome.

mathwhiz | January 21, 2019

Guess I should comment, given the last two posts...

@markcohen ... The symptom on my Model X is absolutely not a grinding or groaning sound, so not sure what that is. The only sound like that I hear is from when my brakes are wet, but that goes away quickly and has noting whatsoever to do with brisk acceleration.

@Melania ... Not sure who you're suggesting for the tow hook but that's a big no from me. My tow hook has been stowed in the hitch receiver bag since I took delivery.

markcohen | January 24, 2019

@mathwiz, sounds like our issues are different then. So far - knock on wood - mine is gone. Perhaps it was the un-tightened plastic door. Hard to tell. @Melania, it is and was not the tow hook.

tedgavin | January 25, 2019

It's called "acceleration rattle" and is a known issue. It can be repaired in your local dealer's service center with replacement of a couple parts and is covered under warranty. It's not a safety issue and the car can be driven just fine without it. I had mine done in about 2 hours.

jch | January 26, 2019

@tedgavin great information. thanks! I will take mine to service center.

theresathurber | January 26, 2019

I have experienced the same problem after the car had been driven about 4k miles. I took it to the Tesla service center and they dismissed it as a characteristic of the vehicle which I don't agree with but they have yet to fix the problem which is only getting worse. I will try again now that others have had it diagnosed and given it a name.

tedgavin please post the outcome of your repair. I'm tired of the excuses I keep getting from the service center and it is hard to accept the vehicle sound as an inherent problem I'm supposed to just accept

jjgunn | January 27, 2019

Awhile back, Tesla updated the front half-shaft parts (to rev B) to overcome a 'front end shudder on acceleration, more likely on air suspension settings above LOW'

I'll update after my appointment on 04-Feb.
I've seen other posts by you mentioning the half-shafts with proper part number. Thx for that. Super helpful when I head into the Service Center on Feb 11.

I was driving around a roundabout maybe 5-7 MPH when I heard a clunk in the passenger side front wheel. Almost like a wheel bearing might be wearing out. Also hearing squeaks equivalent to a squeaky bed frame in the front end. I have just under 16k miles on my MX & always drive in "Low" position.

Time to invoke the warranty.

info | February 3, 2019

Received my MX back from service 30 days ago and while excelerating on an entrance ramp I heard a growling / grumbling / growning noise from under the front part of the car, sounded as though it was coming from the electric motor, tried it a few times and it repeated the same noise. Took out the car the next day and tried to repeat the issue and nothing. Made an appointment with SC . They are busy till April 4th. Third day out no noise.

mathwhiz | February 4, 2019

Update: Took my Model X to Costa Mesa Service today. Quick review is that last year I had the front-end shudder that develops (after about 10k miles, in my case) on quick acceleration, for which they designed the updated rev B front half-shaft parts to fix. The service techs went out for a drive with me so I could demonstrate the new (and more subtle) front-end 'rattle' on acceleration that has developed since replacement with the rev B parts. True to the old adage that intermittent problems seldom show themselves to repair techs, I had a helluva time getting a demonstration... :-( I told them of my hypothesis that, though the rev B half-shaft parts improve on the problem symptom, they don't completely resolve it. So over time a new and more subtle failure indication is developing. They admitted that this is correct, and that the problem remains with engineering for a more complete fix. For the present, I agreed that I can live with the issue while they work on improving the design. But, I also pointed out that I am literally paying for the flaw with increased tire wear from keeping air suspension set to Low. So, my patience is not infinite...

To be fair, the original 'shudder' was a symptom that was like 'a tire iron over the head', in comparison to the newer a much more subtle one (in my car). Although I am expecting it to get worse over time, to the point where I will eventually demand that action be taken.