Wrench589

For those experiencing vibration, I trust the vibration is in both V4 and V8 mode, because it would be a waste of time to try to fix vibration that is only in v4 mode. V4 mode will definitely generate some vibration and the bottom line it - we are stuck with it. A V4 engine is inherently rough running. Counterbalancing can correct it, but then it would be horrible in V8 mode. So, GM has to balance it for one or the other, but not both. Since V8 mode is more important, that's where it gets balanced. Bottom line - if V4 mode vibrations are too bothersome, then a GM is not for you. Get a Ford Ecoboost. Not trying to be a smart ass, but that's an unfortunate characteristic of these Active Fuel Management engines. Alternately, get a programmer from the aftermarket and turn the AFM off.

I stand corrected! Thanks.

I'm not sure if this is good news or bad for those of us with this issue. I did a query on SAEs website to see what kind of technical papers may have been written on this kind of issue, if any. I searched for "booming" as the SBs I've found use that term to describe the pressure/noise we are experiencing. Guess what I found? http://www.sae.org/search/?qt=Booming&sort=relevance&sort-dir=desc&display=list&taxonomy=&sector=%28%22AUTOC%22%29&content-type=%28%22PAPER%22%29 Hundreds of papers written by those in the automotive industry regarding booming noises in automobiles. I even found a couple of papers on line that mention the pressure sensation associated with these low frequency sounds. So, this issue is nothing new to the industry, and there is lots of science out there. That's the good news. The bad news, is this is a complicated phenomenon, not easily corrected. Complicated even more by the fact that some vehicles don't exhibit it, and some don't initially and then suddenly develop it. Even Jansondenali mentioned that with his second Escalade. Of course, this is way beyond what the dealer can do. This is GM heavy engineering stuff. And, to really make it interesting, check out this write up on the GM Terrain when they brought it out. http://www.engadget.com/2011/02/25/gm-shows-off-terrain-suv-with-noise-cancellation-says-silence-e/ So, GM knows all about "booming" noises in the vehicle, especially when running the engine at low rpm's for improved fuel economy. The solution - try to use noise cancelling technology to hid it. Of course, if the noise cancelling system doesn't work well enough, then the noise will still be heard. Of course, that doesn't explain the vehicles that don't have noise cancelling, like the Yukon SLE and SLT's. The plot thickens!

"High strength steel" is a very generic term. Could be any number of steel specs, and I don't know which one GM uses. And, I don't know what grade of steel "standard" frames and body parts have been made of, but I'm sure that has evolved over the years. That said, I would be surprised if the automotive industry uses A36 for frames. A36 is a structural steel spec for standard rolled beams and other standard structural shapes. Frames are typically formed by the automaker, likely from some plate or bar material. But I wouldn't presume they use A36. There might even be an SAE spec that they use.

All the high strength steel they are using is a concern. GM uses high strength steel because that allows them to use less of it, to reduce weight. So, they thin everything down. Will have the load capacity due to the higher tensile steel. But, less mass means all the natural frequencies of everything will change, typically go down. So who knows what could be resonating in the frame/chassis. It's all one big inter-connected system and is complicated as hell from a noise, vibration and harshness point of view. I wouldn't want to be the engineer at GM responsible to sort this mess out. And I definitely wouldn't want to be the designer responsible for making it!!

Definitely be interested to hear the results if you install the Bilstein's. I agree that there us something up with the suspension. And, my Yukon XL is also exhibiting vibration much like you folks are with the pickups. Question, though. I've got the electronic active control shock absorbers, as well as air ride on the rear. I'm not as familiar with the pickup builds, but does everyone having vibration problems also have active shocks? If not, I'm thinking the standard shocks and the active shocks are likely quite different. And, the suv's have a coil spring rear suspension. Yet, both platforms seem to have the vibration. Curious.

Tobtek, have the rear end gears been replaced yet? For what I'm seeing on the tahoeyukon.com forum, replacing the rear end gears is the only thing that has worked (twice, so far) to eliminate the buffeting/drone/pressure problem. My take is that there is something NG with the original gear sets that is the root cause of the buffeting/drone/pressure. But, the overly stiff shocks makes it even worse. Fix the shocks and the harshness goes away, as does some of the buffeting/drone/pressure, but also need to have the gears replaced. And, by the way, need to have both rear and front done. One of the folks on the pickup truck forum dealing with the "vibration" issue noted the dealer changed the rear end gears and the vibration went away....until he put it in 4wd! I notice more vibration in the steering wheel in 4wd. And, the vibration is the root cause of the buffeting/drone/pressure, I think. Replace shocks and both gear sets, and we might just be out of this mess!!

Tobtek, that's awesome. I'm extremely encouraged to hear that the new shocks solved the harness of the ride. I've always felt it was way too harsh. Now I just have to convince my dealer to get them. I can't recall, but were you also having the buffeting/pressure issue? Did the shocks solve that too?

I share you concern that if perfect balanced tires solves it, then it will be a short lived solution. But, if it turns out to be somehting inherently wrong with the crown and pinions or driveshaft, then that is a different story. That is permanently correctable. And to be honest, the crown and pinion or driveshaft is something that 1) has caused these kinds of issues on vehicles in past, many, many times, 2) it carrying enough energy to excite anything in the vehicle to annoying levels. I must admit that I'm still struggling to see it's the crown/pinion or driveshaft since mine seems sensitive to road surface, but vibration is a crazy thing to locate and resolve sometimes. And we can't ignore the two reports of new rear end fixing the issue.

Yea, definitely good news. Correct if I'm wrong, but I believe this is the second time we've got a report of one of these suv's having the problem fixed. Quite some time ago, there was a post on one of the forums from someone who worked at a dealership that they changed the rear end in a customers vehicle and the problem went away. Now, same thing again. So, that is very, very compelling evidence. Now, this fella is saying the problem is still there when he puts it in 4wd....yea, because the front crown and pinion is NFG too!! That's a no brainer - need to change them both. Looks like it's time to call the dealer....

Fingers crossed, buddy! I hope you're good to go. Keep us posted one way or the other.

Dozzer, that a very interesting story. I'm not surprised that the dealers have trouble Roadforce balancing. Let's face it, how many tires do they routinely balance at a dealership compared to a tire shop? Now, add in the complexity of doing a Roadforce balance properly and it does not surprise me that they can't do a very good job. I've read the manual for the Hunter GSP9700 and it's not for the faint of heart. If you want a good laugh, search for Hunter Road force balance on YouTube. You'll find all kind of clowns trying to show what they know. One tire shop was even so stupid they posted a video about how to Roadforce balance, and they did not use the roller at all! All he did was a simple dynamic balance! Yet he was trying to advertise for his tire shop. Doing Roadforce balance. Clown! Now, having said that, the Roadforce numbers your dealer achieved at 18lb and 24lb are withing GM spec. GM spec is 18lb for P-metric tires on a car, 24lb for P-metric tires on a light truck, and 35lb for LT tires on a light truck. Now, I agree with your tire guy that said they should not have returned it with a tire at 24lb when they are trying to solve a vibration problem. But, there are two other things to consider: first, it is likely very important to match all 4 tires on these vehicles. Having one tire generating 33% more road force then the tire across from it! can't be a good thing even if 24lb is in spec. Second, I think GM's spec is too high. I believe it is the same values they have been using since they started using Roadforce balance machines. But, vehicles have changed over the years. This new generation of vehicle is very stiff - stiff suspension, stiff frame, stiff body mounts, stiff stiff stiff. GM needs to update their specs. For comparison, the default limits in the hunter Roadforce balance machine are 26lb of P-metric tires and 39lb for Lt tires, but it clearly says those values are only a guideline. Clearly, a tighter limit is warranted. And then there the whole thing about doing the "Lateral Force Measurement". I wonder how many dealerships are doing that, or even understand it. What do we do? I'm thinking unless I stand and watch the dealership do the Roadforce and Lateral measurement and correction, having them do a Roadforce is pointless. If it works, great. If it doesn't, needs to be done at a proper shop. And, not all tire shops will do it right. I was shopping for tires about a year ago and one of the local tire shops told me Hunter Roadforce balancing is a joke and the machine don't work. In other words, he doesn't know how to run it! So, shop around.

Tobtek, I completely agree with what your are saying. The entire vehicle package is too stiff and is overly exciting the something in the body that makes the "booming"/"buffeting" sounds and the pressure. GM likely knows what is resonating, but knows darn well there is no easy fix short of scraping the entire platform. And reading the pickup forum, it suffers from the same root issue - stiff ride, vibration, etc. the difference with the pickup is they don't have a massive steel shoebox on top of the chassis that resonates like a guitar box! GM changed many things on this new generation vehicle - everything from the 3 piece welded frame to high and ultra high strength steel for many of the body parts. Going to ultra high strength steel sounds great. Means they can use less of it. Problem is, mass absorbs vibration energy. Make the thing too light and all kinds of vibrations can be excited. I hear you about BMW. But even their Sport ride vehicle will be far superior to this new Gm platform. I doubt there are vibrations and booming sounds! So, GM screwed something up on this design. Not sure if you checked out the link I posted about the 1999/2000 GM pickups, but basically the same issue. Vibrations that they could not resolve. The link has a TSB about the fix, which included a bunch up upgrades (that were done on the 2001-), including different streering box, reinforced mounting brackets, different rubber mounts, to name a few. All to isolate the road vibration from the frame/body. So, I believe there is something very similar going on with this new generation and until GM figures out the path the vibration is taking, and how to isolate/dampen it, there will be no fix. To those of you trying to decide if you should buy one of these, be wary. There is nothing to suggest a new one will be any better.

You may want to post your question over on the SUV threads. Your issue may be the same as the this one: http://www.gm-trucks.com/forums/topic/162779-2015-yukon-noise-in-cabin/ Just curious - why would they have had to replace the headliner to fix a water leak on the side window? Seems odd.

Not to make things seem worse than they are, but the following link suggests this isn't the first time GM has had serious vibration issues on their vehicles... http://agmlemon.freeservers.com/index.html

Any chance you can post a link to this document? I would like to have a read. Check this out.... Not GM's first rodeo! http://agmlemon.freeservers.com/index.html

Jeez, WTF! Haven't experienced any other issues with 4wd on mine. We have been leaving in in 4 Auto for the winter, but I did switch back and forth to 2 WD and didn't notice any difference. Haven't put it in 4Hi more than once or twice, but don't recall much issue. Do you usually leave it in 4Auto? Sounds like something mechanical so no reason not to expect a the dealer can fix it. For those that don't know, Do Not leave it in 4 Auto year round. The front differential will wear out at about 60,000 km for some reason. Don't know exactly the deal, but something doesn't disengage in Auto and wears out prematurely. I believe there is even something in the manual about it.

Yes, very interesting. But, wouldn't explain the vibration in mine, because on mine, the vibration virtually goes away when the road is extra smooth. So, the vibration itself seems road roughness induced, if that's somehow possible.

I know I wouldn't mess with mine if it was OK! I agree there is more chance it's an assembly error, not component defect. Especially if hub-centric is a new thing. Someone didn't communicate properly to the line and next thing you know, it's being done wrong. Wouldn't be the first time something like that happened. And you're right - they have no fricken' business using impact wrenches to put wheels on!

Question - are all the wheels on the 2015's hub centric, including the 1500's and the Tahoe/Suburban/Yukons, or just the 3500 dually's? I've got the issues on the "noise" thread over in the SUV section of this forum and wondering if my Yukon also has hub centric wheels. (Which in theory are supposed to be perfectly entered, as long as the hub bore isn't too large or the hub too small!).

Interesting. I've observed on mine that the noise and buffeting occur when the heater fan is on. I also turned the hvac system completely off and didn't seem to make any difference, but I might play around a it more with that if someone else has seen an affect.

It might be an issue of differential temperature. Cold outside, warm inside with the heat on. Or, hot outside, cold inside with the AC on. Or, any exteme temp, hot or cold, from the temp during assembly (I've seen this at work many times on industrial machinery).

38 mph (60 kph) is definitely where mine really starts to be noticeable. But it persists up to 80 kph, diminishes somewhat, seems real bad at 100 kph again, then diminishes again by 120 kph. I too am thinking more and more that the vibration is totally related to the noise/pressure. They feel/sound completely in sync when it's 'rocking and Rollin' at its worst. I find Romanbasi's story totally fascinating. Thinking back, I do recall an extremely cold day here about a month after we got it. The vehicle is always parked in our heated garage, but we took the kids to skating lessons and it sat outside for a spell. I remember the day because it didn't start all that great and I was thinking "oh, oh, I hope this isn't going to be an issue" now that I think about it, it is possible,I first started to notice the noise/pressure around that same time. Can't claim as distinct an observation as Romanbasi, but maybe..... Observations like this, that show a distinct change in the behaviour, are incrediably crucial in determining a root cause of this issue. This is extremely helpful. Thank to both Romanbasi and Jasondenali15. Thanks guys! As for taking it in to the dealer for the roof fix, yea. Pretty hard to avoid giving them a chance to fix it. I think most lemon laws give them several attempts. We don't have any lemon laws in Canada. The Ontario government was going to pass one, but the big three petitioned them not to, offering to set up an "independent" group to arbitrate these issues, funded by the automobile industry. Since it wouldn't cost the government any money, they agreed to it. So that's what we got stuck with!!

Actually, I think this link is absolutely referring to the same problem. I maintain mine has the same "rough" ride and vibration, and like was said on that site, "you feel every pebble and bump" on the road. I also observe that when the road is extremely smooth, the vibration goes away and so does all the annoying noise and pressure sensation. Lastly, someone on that other site mentioned "reverberation" - definitely referred to sound/noise.

To add to this, Anon has 2 or 3 of these vehicles and none of them exhibit the issue. He confirmed the first 2 have cross bars, but didnt say about the third. I recently rode in a Tahoe LT that has cross bars, and I can definitely hear the noise and feel the pressure. So, not to encouraged to think the cross bars will solve it. That said, both cross bars were near the back of the vehicle, so it is possible there is an optimal location. Worth playing around with....