Vibration (like buffeting) 68-73MPH new tires, 3 different shops checked
- Thread starter smokey_2020
- Start date
NVH app suggestions
I'm sure maybe too close to a wheel balancing but have the hub surfaces (hub and wheel) been cleared of rust and debris?
I do have a torque converter shudder on the low speed if I barely accelerate, the car is shuddering (washboard effect) not small shudders but unmistakably big ones. Local shop checked (by hand) for bearings and CV joints but told me that this type of inspection will not expose the problems with bearings or CVs.
It brings me to a question if torque converter is starting to fail at low speeds, can TC cause 3rd order vibrations at high speed. I am not finding TC in the list of 3rd order causing problems. Thoughts?
It brings me to a question if torque converter is starting to fail at low speeds, can TC cause 3rd order vibrations at high speed. I am not finding TC in the list of 3rd order causing problems. Thoughts?
I have to ask. How much money have you spent chasing this problem?
with new set of tires ~$1350
Have you had any brake work done?
no not yet
I had a set of tires road forced from a reputable shop and cleaning the hub faces was part of the money spent. Unfortunately, there's no clearcut defect that you can nail down, so throwing parts at it until it's found, or waiting for it to get worse are your options. I hate vibrations and had one like this, but I traced it to the slide pins. For those who say the location of the one with the rubber doesn't matter, it did on my ride. I still have a car whose tires vibrate on certain roads but not others.
Yes, it is a massive disappointment to trade-in this otherwise fine truck, it has been the best highway cruiser for us. I wanted to keep it at least another 3-4 years. We enjoyed it immensely.
I will present results of NVH app to the dealer and will ask for Pico-instrumented test, it is at their discretion - they either would try and find the source of the 3rd order harmonics and Pico can be effective at isolating the source (if an operator knows how to use the Pico tester) or they will send me pack sand.
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In the spirit of keeping up with updates, I took the car in, the dealer did the Pico test and came back saying that my NVH application 3rd order vibrations are not confirmed with the Pico.
That concludes my budget and waste of money trying to pinpoint the vibration. Vibrations that plugged your ears or sensed with your eardrums are more common than I thought, some of the Mazda CXes and Kia Tellurides/Palisades had that issue. Dealers never acknowledge this types of vibrations as they are not "problematic" or "dangerous" and manufacturers are not paying for these type of troubleshooting.
Prices of the full size SUVs are insane at the moment, I need to drive with plugged ears... for a bit longer until gas prices slow down sales of full-size SUV.
That concludes my budget and waste of money trying to pinpoint the vibration. Vibrations that plugged your ears or sensed with your eardrums are more common than I thought, some of the Mazda CXes and Kia Tellurides/Palisades had that issue. Dealers never acknowledge this types of vibrations as they are not "problematic" or "dangerous" and manufacturers are not paying for these type of troubleshooting.
Prices of the full size SUVs are insane at the moment, I need to drive with plugged ears... for a bit longer until gas prices slow down sales of full-size SUV.
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Don't take this the wrong way, but is there any possibility that your hearing and/or senses have become overly sensitive to the perceived noise? If your wife and many others cannot hear or feel the noise/vibration, I doubt it is very perceptible.
The reason I ask is because a very close elderly friend who had hearing loss complained about similar tire/harmonic vibration noise that no one else (dozens of passengers) could detect in his minivan. This went on for several years until the tires were replaced and he claimed the noise disappeared. No one else ever heard the alleged tire/harmonic noise, including myself after driving it for several hundred miles on numerous road trips.
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It is absolutely fair, I suspect I have that problem, mine is opposite, I was measured by audiologist to far exceed my age hearing, I was still hearing up to 18.5kHz, but definitely, I am outside of the normal bell curve.
What was disconcerting, that the guy who wrote NVH application, was the same guy who worked on the Pico tester that GM dealers are using. He basically replied to me saying that none of the dealers know how to properly use Pico testers, and thus results cannot be trusted. The dealer tech, of course, told me that this $100 NVH app that I purchased is just a toy. One of them is correct, but who is?
Probably they are both correct, but at the end of the day we as car enthusiasts lose in this game. Given that I have been building AI products for the past 14 years (before people even knew what AI stood for), I am seriously tempted to take time to build an AI-techician solution that would have many purpose-built wireless sensors that could be easily instrumented by an owner and do 80% diagnostics. There will always be 20%, but with time as model would learn from new data and accuracy would improve that 20 would become 5.
Do you think that there may be wind getting in somewhere at that speed?
I've seen cars driving down the road with plastic belly pans and other parts flapping in the breeze.
I don't think they ever noticed though.
I don't think they ever noticed though.
JHZR2
Staff member
That looks like a complex app and I’m not sure what they’re even showing.
I’ve used the iPhone accelerometer for years with very good outcomes.
Let’s get some raw data and look at it.
Ideally you’d measure true circumference of all four tires, but mfr data is good enough to start.
Take a snapshot at 60MPH, and then take some others at speeds of interest. Just have to do the math to determine frequencies.
When we get some real fundamental data it may be more indicative. I can’t make out what your app is telling you, and I’m not sure what inputs it takes either.
NVH app is running on iPhone using it accelerometer (from what I gather). It is mounted in the rigid mount on the dashboard (middle of the dash). I am posting the actual data.That looks like a complex app and I’m not sure what they’re even showing.
I’ve used the iPhone accelerometer for years with very good outcomes.
Let’s get some raw data and look at it.
Ideally you’d measure true circumference of all four tires, but mfr data is good enough to start.
Take a snapshot at 60MPH, and then take some others at speeds of interest. Just have to do the math to determine frequencies.
View attachment 332565
When we get some real fundamental data it may be more indicative. I can’t make out what your app is telling you, and I’m not sure what inputs it takes either.
ChatGPT indicates (but I did test driving at this speed, I press Neutral button but vibration is still there)
1) Driveline harmonic (VERY common on 3.0L + 4WD)
- The inline-6 diesel produces strong low-RPM torque pulses
- At highway cruise (~65–70 mph), you’re typically:
- in 9th/10th gear
- around 1,300–1,500 RPM
- That combination can excite a driveshaft resonance
This creates a low-frequency standing wave in the cabin- Not felt as shaking
- Felt as ear pressure / head “drumming”
Supporting pattern:
- Happens in a tight speed band
- Feels like pressure, not vibration
- Doesn’t show strongly in steering wheel
- U-joint or shaft imbalance
- Driveshaft harmonics reported by owners at similar speeds
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JHZR2
Staff member
I don’t know how they’re coming up with nth order harmonics, attributed to various things, when I don’t see a plot of the type I shared.NVH app is running on iPhone using it accelerometer (from what I gather). It is mounted in the rigid mount on the dashboard (middle of the dash). I am posting the actual data.
ChatGPT indicates (but I did test driving at this speed, I press Neutral button but vibration is still there)
1) Driveline harmonic (VERY common on 3.0L + 4WD)
- The inline-6 diesel produces strong low-RPM torque pulses
- At highway cruise (~65–70 mph), you’re typically:
- in 9th/10th gear
- around 1,300–1,500 RPM
- That combination can excite a driveshaft resonance
This matches your symptom almost perfectly.
- Not felt as shaking
- Felt as ear pressure / head “drumming”
Supporting pattern:
Also consistent with known driveline causes like:
- Happens in a tight speed band
- Feels like pressure, not vibration
- Doesn’t show strongly in steering wheel
- U-joint or shaft imbalance
- Driveshaft harmonics reported by owners at similar speeds
View attachment 333698
View attachment 333699
View attachment 333700
I have multiple I6 diesels, and an I6 gas, and they’re all incredibly smooth.
Seeing an actual frequency at which there are elevated vibrations, and then multiples thereof, helps to ID tires vs other things, imo.
Yes, I think Duramax 3.0 is incredibly smooth on this vehicle, in fact this is one of the best engines I ever owned over the years, it puts 5.3 to shame.
I realize that chasing this problem is incredibly hard and now getting expensive, new set of tires, multiple dealer visits, etc. but I visited local Chevy dealer and my $46K Tahoe LS with diesel that I bought 3 years ago is now min of $80K+, which I simply cannot afford.
These are the only plots I have, NVH phone app and GM Pico test. They cannot be more different. Regardless, eardrum pressure is there with new tires, same 63-73MPH band. With new Defender tires, eardrum pressure is less obvious but it is still there and enough pressure to keep me popping my ears at this speed.
I forget which channel, but I recently watched a video where they were troubleshooting a similar problem, and it turned out to be dirt/rust on the brake rotor and hub. Previous repairs never properly cleaned the tire/rotor/hub mounting surface, so they got very strange vibrations. Also, your comments on the NVH app (and your software dev experience) , and having previously worked on iPhone development back in the iPhone 3 days got me wondering- do you have a different iPhone you can use for the NVH app ? I am thinking perhaps use another phone, transfer the software, and validate the previous readings. Its possible that the accelerometer could be better/worse than your current iPhone. I used to work in the communications industry with cell providers and we did have problems with the same model phone having different tolerances / efficiencies on the cell bands, validated through huge amounts of data collected to troubleshoot customer rx/tx issues. I recall that at that time, Huawei and HTC cell phones had far more variance than other brands. Or maybe via social media and the NVH app you can find somebody close to you that has the app on their phone and you can do a test.