The Zip

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blackout07 - give Breckenridge more credit than that, he wasn't a fooled customer, he was informed before he logged onto the thread. I, like you, are not experiencing these issues, but the few that are voicing their frustration is no indication this is not widespread. Also, the dealer is trying to make a sale.

jasondenali15 - make an adjustment (if you did not take the truck to the shop) in accordance with the private message. I have been focusing on pressure, but your comment "You are right on the money with that assessment", infers noise and pressure can be managed at the same time, at least in your truck. After the adjustment, provide noise and pressure percentages now compared to right after the dealer installed the plugs.

wrench - agreement with your comment, "I feel there is something inherently "wrong" with these vehicles and it's not a simple matter of something that broke and can be replaced to fix the issue. Something way more systemic and difficult to correct."

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breckenridge - All folks are not experiencing this issue, but a person would have to know what is. The thread has evolved but the first two post are good initial descriptors. Pressure/Buffeting/Shaking/Vibration are now issues on this thread with mostly pressure and buffeting dominating the day. Texassweetea test drove the most and would probably say you would know it from day one. You may get fortunate and find one without any issues, but one thing not in your favor, GM extended model fullsize SUV's seem to have the problem more versus the shorter versions.

jasondenali15 - that does make sense to me. Compared to driving before the plugs, what percent did the plugs (when first installed) decrease pressure? What percent did they (when first installed) increase noise? I'm guessing 90% both ways. The increased (noise) and decreased (pressure) occurrence should have been very close if not simultaneous.

jasondenali15 - I'll send you a private message later this evening. Transmission louder after the plugs, correct?

Jasondenali15 – wrench mentioned dealers look at you folks as “buffoons” and “idiots” for trying to get some relief by using cotton or foam for this issue, so I won’t suggest another option. You stated in an earlier post that the plugs worked. Put the plugs back in and tape them in place this time, maybe the one falling out compensated for the other two. Doing nothing while still driving the truck will make your situation worse. Also, a post identified a dealer who changed out the rear end and the problem was solved, ask your dealer about this.

jasondenali used mic plugs, but he never took a picture or provided an update after it was installed, but you did provide a picture of the cotton balls, both methods worked. As for the cotton balls, the headliner is flattening them out or they are just moving. If you can stop either from moving, the time without pressure may be extended. The headliner movement is a big deal, but we don't have a lock on that, yet. But the cotton balls worked, so if you stop the cotton balls from flattening or moving you may have something. Try taping the cotton outside of the mic and inside the O ring, put the grille back in place, then tape the grille instead of the cotton. If you isolate the space occupied by the cotton balls, headliner movement may not affect them or have a decreased impact.

Pushing on the flexible part of the headliner while the vehicle is off, windows up, and in park may have similar effects as driving or towing. Probably not electrical or mechanical, but a R&D error in headliner flexibility (just talking pressure)

Went to the GMC dealer to pick-up some grilles (actually called grilles) to do some testing with the Mic Well, but the cost was 26 bucks. Too expensive for me to conduct testing when its not going to benefit me. But I did find out the grille can't be sold separately, it comes with the mic. This would suggest the mic comes off. Someone take a flashlight and look around in the mic area, there may be a screw to take the mic off. That would be an option equivalent to pulling pins or disabling the mic. If that is the case, there would be no need for cotton, tape, ear plugs, mic plugs, mic well, or anything else that was mentioned.

20sierra did not use the cotton with the grille, the grilles were left in the cupholder. There was nothing to hold down the cotton that's why it moved and needed to be replaced. Part of the Mic Well concept is to keep the cotton in place, or he could give the grille combined with the cotton a shot. The grille combined with cotton should keep the cotton within the center of the mic, but will do nothing around the mic. 20sierra's concept is to put cotton in the center and around the mic. Another part of the Mic Well is to isolate around the mic. And if cotton is used, to keep it in place. Keep in mind the Mic Well wasn't fabricated to use with cotton, but if cotton is used it will keep it in the center, around, and in place.

Tobtek - Deal with the booming, wait for GM, keep complaining to the dealer, or doing something about it are your only options. I know folks laugh and make jokes about the recommendations for doing something about it, my answer to that, So freakin' what. The cotton balls worked in one scenario and Mic Plugs worked in another. Someone else commented their cotton balls made the situation about 5% better. How much movement is in your headliner? If you think it is excessive (compared to mine that does not move at all), the cotton balls will not stay in place. If they don't stay in place around the mic, you shouldn't notice a change. The cotton balls work, but have to be readjusted every so often because of movement.

All - personally, I’m a big boy and I can handle my business whether I’m wrong or right. But don’t trash others for wanting to get some relief for issues the manufacturer does not acknowledge unless you jump through hoops. It’s unfortunate this thread has gotten this big, but this info repeats itself and it would benefit current and perspective owners to read the early pages. Let's get the thread back on point. I agreed my posts can be shorter, so if I can help (even if its just one person) and I need to say it in longer than 4 lines or so, I’ll send you a private message. At the end of the day, everyone will ultimately do what's in their best interest, regardless of what's posted.

Ok wrench, I agree. Some of my posts could have been shorter, I’ll give you that. But that’s about it. Folks will do what they can to get relief. I’ll tell you what, you can be a Big help. Go ahead and have your rear-end changed out then you can advise the people using cotton or whatever whether or not it can be removed. Sounds like a plan? Time to get the Super Bowl party goin’.

Wrench - it's obvious my information is not for you, got it. Everything on this thread has been repeated too many times to count, so you don't have a lock on original information. My comments are not based on what you or GM did, we know GM's concept don't work and as for you, no comment (yet) I am not experiencing any buffeting or pressure associated with this thread, pulling a fuse won't change that. Now that you are extremely confident ANC is not the cause of the pressure and buffeting, what's next? A recommendation to mitigate what you found would be a good start if you have something to bring to the table, I'm sure folks on the thread want to know. Ok, lets go with "THE ANC HAS NOTHING TO DO WITH IT!!!". How does this help somebody out. Whoop dee do, so what. If you were reading this thread, you would know it doesn't matter about the cause, people just want the effect taken care of.

None of my concepts are scientific, and I am not a subject matter expert on sound. This is just me thinking out loud. This is what I believe to be happening: Bumps, irregular roads, curbs, engine transition, etc, etc, is causing the roof liner to move waaaay more than it should. When this happens, the mics are mitigating resonance caused by too much movement by the headliner. At the same time, the mics are cancelling noise from the other items listed above. If the headliner was stable, the mic would just be cancelling noise, the pressure would probably not be there. When the dealer plugged the mics, it mitigated pressure, but did nothing for the noise. A photo of what the dealer did would have provided good info because a Mic Plug could be modified to mitigate noise and pressure, although not as good as the Mic Well concept. This is what I recommend to do about it: Right now the mic is in an open space compensating for noise, resulting in pressure. I think the Mic Well will help with the noise and pressure. The Mic Well places the mic in a confined space, allowing the mic to operate normally to mitigate the noise while being encased in a “well” isolating it from resonance caused from too much movement of the headliner. As a residual, the Mic Well should also mitigate the pressure. Mic Well and Mic Plug. The Well is designed to affix onto the grille (post 616 as a reference), the grille placed back in it’s housing (post 498, pic 2 as a reference), the Well encases the mic. Two configurations (rectangle and square) because I don't have a grille for exact measurements.

Breathe should have been taken figuretively. What should have been said was "need a little room at the base of the mic for noise cancellation".

Went to the GMC dealer to pick-up some grilles, Parts department only work Mon thru Fri so it was a no go. I initially fabricated a half circle mic well, but then changed it to a square mic well to fit between the pegs of the grille. This square mic well, affixed to the grille, should neatly encase the mic when the grille is put back in place. The mic plug "fitting snug" in place, should mitigate the pressure (one concept may not work for all). But placing the plug snug will silence the mic to where it can't initiate the process of cancelling noise. What this infers is the mic plug should fit snug but it should not come in contact with the base of the mic. The mic needs a little room to breathe for noise cancellation, but snug enough to mitigate pressure. This is if you use the mic plug, I'll talk about the mic well later, I think this is the better option for noise and pressure. It would be great if you guys can apply these concepts, but when I mention fabricating, the information may be more for dealers.

biginjins - got it. Sore subject with me and the roof rails being a safety hazard, early on in the thread I was on GM pretty hard 'bout that, think that's why I have warning points today. Because of the different things that may be causing the pressure and buffeting, we should circle the wagons on the pressure issue, we are close. Then transition to the noise as we build steam. Your vehicle (Suburban) doesn't get a lot of playing time on this thread, mostly Denali and Escalade extended versions. My vehicle (Tahoe) headliner does not have any flex at all, other than around the air vents, when I touch my headliner it's as though I am touching the roof. Current conversation on this thread about the mics will not help Chevy owners because the mics are covered under the headliner. But if it's any consolation, I think the Chevy headliners are better built, mine appears to be a couple inches of one piece dense foam, affixed to the roof. Does your headliner appear to be the same? If so, the common denominator to the pressure would be your extended version Chevy.

What works for pressure up to this point; cotton balls placed around the mic and foam mic plugs placed into the mic O ring (may not work for eveyone, but this is based on it worked, may need minor adjustments). This provided some relief but the goal should be as close to 100% as possible. Excluding what GM is "not doing", what it is I "am doing", and whatever it is the dealer "may be doing", where do you guys go from here? This thread is terrible with providing requests for information (RFI). You guys can really help your cause by providing RFIs when requested. Dealers are reading this thread. The more information, the more they will have to work with. (they’ve already plugged the mics, where did they get that from). The less information, well... For all the folks on this train, if it's moving too fast and needs to throttle back, just say so.

Wrench - I'm with you, continue providing feedback. But until you find the root cause, a fix, somehow ensure the dealer fixes it correctly, or GM decides to buy back your vehicle, what else there for you to do is mitigate it. The options provided on this thread may or may not work the same for everyone, lot of reasons why. But the "current" options singularly or in combination may give the customer some relief until there is a "better" option. Doing nothing until or if there is a fix, should not be one of those options.

Hey, where are you guys going. This is headed toward trying to fix a cause instead of addressing an effect. The causes are so many that GM or all of the brands haven't been able to find a fix (read the early pages). So that leaves the customer to find the fix? Even if the customer does get lucky and tells the dealer the transmission is the fix, for example, is the dealer going to change the tranmission based on what the customer thinks? Good luck with that. Because of all the causes, if there are no ideas followed by action to mitigate the effect (buffeting/pressure), this thread will stall.