Banging noise over bumps

[ZapM3]

Has anyone experienced or learned about a banging noise coming from the rear of the car when going over bumps? It seems to happen almost exclusively under hard acceleration. It happens on my M3 (26xxx) anytime I encounter a fairly minor road imperfection while flooring it. My main theory is that it was from the motor quickly cutting power from a sudden loss of traction. My secondary theory is that is from the rear suspension when it is compressed from the weigh shift to the rear and then gets compressed further by the bump.

I can't seem to find other reports of this on-line so I am about to make a service center appointment. But I figured I would check here first. I've taken all personal items from the car, including the charging adapter, and it still happens. It is not a minor noise. It is fairly loud.

 

[ewoodrick]

See what is in your trunk. Is it may the charging cable?

 

[Twiglett]

Those darned pedestrians

 

[LBusDoor90]

I have it too. I have just assumed it is the lid over the trunk well getting a little airborne and then slamming when it comes down.

 

[boaterva]

OP already said the UMC was removed. But yeah, remove everything to see if it’s a built in issue or not!

 

[ZapM3]

... remove everything to see if it’s a built in issue or not!

I tried removing everything and the noise remained. So it’s definitely coming from the car itself.

The noise doesn’t bother me much. I love the car. I’m just worried that something is getting stressed in a way it’s not designed for and may eventually fail.

 

[SMAlset]

Are you sure it's not your tow hook stashed somewhere. In our MS it was in the rear in a side compartment I think. Not sure about the Model 3 as I don't have mine yet. If you know where the hook is and it's not that, then definitely call service to have it checked out.

 

[boaterva]

I believe the 3 is the only current car that actually has a built in storage spot for the tow hook (under the mat in the frunk). You’re right, though, it could be rattling around somewhere. Could also be noise radiated from the front, but unlikely.

Is the sound system subwoofer in the trunk area and that could be loose? Thinking of largish items that are ‘built in’ here...

 

[dduffey]

Yes has happened to mine twice, both times during hard acceleration over a bump. Also happened to friend's. In all cases the bump in the road was pretty minor (a manhole cover and cracks).

I assumed it was a combination of high impact torque the suspension bottoming out and I now pay more attention to the road when accelerating.

I never got out to investigate the road itself but did check the car because it was louder than I would expect for that speed/size.

 

[effinb]

Haven't experienced that with mine, but a friend did with hers and it turned out to be a loose rear sway bar. Simple and quick fix at service center once they figured out that's what was causing it.

 

[ZapM3]

The cause of the noise was a sub-frame bracket that needed to be tightened.

Concern: #VSC [CAT1]:Hard acceleration and hitting a bump, Customer hearing a pretty loud
bang.
Corrections: Exterior NVH General Diagnosis
Technician verified concern with customer. Technician identified re-torquing of subframe
bracket needed to be performed. Technician performed. re-torquing of sub-frame bracket.
Verified no abnormal noise on validation test drive post re-torquing.

 

[Cornellio]

Yes! I have the exact same issue on my vin 23xxx series M3. So glad I found this thread and documented solution. I will bring this info to a service appointment. Thank you for this post.

 

[annetoneyo]

I took my 2018 Mid Range Model 3 in for service today. Here is what they found:

Concern: Only when accelerating or braking quickly, I notice a clunking and thudding sound coming from the rear of the car. The sound is intermittent, and pops up occasionally when the car is on an uneven road with bumps.

Technician verified customer concern. Upon inspection, technician re-torqued vehicle sub frame and performed validation test drive. Technician verified noise is no longer present.

Correction: Check Torque On The Front Subframe Bolts, Rear Subframe Bolts, And HV Battery Bolts; Tighten Bolts To Specifications

 

[Dan203]

Are you sure it's not your tow hook stashed somewhere. In our MS it was in the rear in a side compartment I think. Not sure about the Model 3 as I don't have mine yet. If you know where the hook is and it's not that, then definitely call service to have it checked out.

That's in the frunk

 

[RandomJohnny]

those of you that had your subframe re-torqued...can you describe the sound with a little more detail?

I have a thump/knock like sound that happens when going over bumps, uneven roads and accelerating out of corner. It is not consistent but it is a rather dull sound. For example, I could pull out my drive and down the bump and hear it. Then immediately go back up and down the same bump and it is gone.

Any sound recordings?

 

[dduffey]

BTW, this was fixed by the service center during a follow-up visit for a different reason. I don't think I mentioned it and don't have my service records, but tightening something in the rear suspension was what fixed it, affecting only certain VINs (Mine is 17xxx).

 

[PNWLeccy]

BTW, this was fixed by the service center during a follow-up visit for a different reason. I don't think I mentioned it and don't have my service records, but tightening something in the rear suspension was what fixed it, affecting only certain VINs (Mine is 17xxx).

Do you know the range effected by any chance? I think I have this issue with a 35xxx VIN

 

[dduffey]

Do you know the range effected by any chance? I think I have this issue with a 35xxx VIN

I don't think so, but I probably had under 500 mi before it was fixed.

 

[firebat]

I have a similar noise. It sounds like large marbles rolling around or creaking, and initially only happened on bumps, but now I hear it pretty much everywhere.

I took it into Tesla 3 times before they finally acknowledged the sound and would even take a look. Once they did that, they discovered that a piston in the rear suspension was leaking, and ordered a replacement. I've been waiting since August, and they've stopped responding for emails. At this point I'm waiting for the rumored Renton service location to open up before trying again. It's incredibly frustrating.

 

[rideincircles]

I have been getting some popping noises coming out of my rear strut over bumps. IT sounds like this may be the issue if it is somewhat common. Its the only issue I have had after 16k miles other than some mild delivery issue stuff that was fixed. I will see if I can schedule an appointment soon before my 4k mile Cali road trip and hopefully get the FSD computer.