Ccamp5

The Denali I purchased has the 6.2L EcoTec3 V-8 engine with 420 hp and 460 lb-ft of torque and a new 10-speed transmission. Drives 10x smoother than the others I had. Definitely no lag in this one.

We recently traded in our 2nd 2015 Suburban LTZ with 90K miles on it for a 2019 GMC Yukon Denali and it does not have the problem either. (Recap our 1st 2015 LT we purchased in 2014 had the problem. Gm bought back the LT 4 mo after purchase and we replaced with 2015 Suburban LTZ. LTZ did not have the problem.). WE have had 3 GMC Suburban & Yukon within 2015 to present and only the first one had the issue, so i would agree with Need For Speed that the problem has been fixed. Both our 2015 LTZ and 2019 Denali drive like dreams!

Wanted to give an update. We now have 23,000 miles on the LTZ and have not had any of the issues we had with LT. Still drives like a dream!

No, Do not worrk for GM. Dealer we bought from is 200 miles from the Arlington Plant.

10th character is F.

Well our ordeal is OVER!!! To recap…we had a 2015 Chevy Suburban LT with a manufacture date of 8/14. We had two main issues with ours: Severe Vibration at all speeds and the buffeting (to the point I have had several ear infections, kids have thrown up in the car and headaches on long trips). After having it in and out of the dealers service center 8 times they called in a GM Engineer. When meeting with the GM Engineer we found out some very interesting things. 1) the vibration is the same vibration that they were having with the newly designed 2014 pick-ups and we were told that there has recently been a change in the manufacturing process to eliminate the vibration. 2) They believed the buffeting was coming from behind the sunroof, and having to do with the cross bar supports coming undone. He stated that some things had been changed in manufacturing process to eliminate the buffeting issue. He told us that he has a machine that they can hook up on the inside of the car that will measure the "buffeting"/pressure. If we did have the buffeting then they suggested the fix of taking the headliner down, sunroof out, and epoxying/gluing the cross beams back to the roof. (FYI…they don't cut the top of the car off as others have stated.) After speaking a while longer we left the car with the GM Engineer for the day. Shortly after we left, We get a call and were told that upon the test drive that the GM Engineer could feel/hear the buffeting without having to hook up the device they use to measure the buffeting. And that ours was one of the worse cases that he had heard. Upon discussion with our Service MAnager and GM Engineer they recommended the fix of taking out the sunroof. We were hesitant but were told that we had to at least give GM the chance to try their fix. We agreed. We received a text from our Service MAnager that stated that there was a "gap" that was bigger than it was suppose to be. After two days we get it back, and of course the buffeting & Vibration was still there. We told them we wanted a new car or we would sue/file lemon law. At this point our dealer was willing to do anything to make us happy. We told them we wanted another Suburban because it is the only vehicle that could accommodate our family. And after speaking with the GM Engineer about their being changes in the Manufacturing process, we had hopes the issue on a new one would be fixed. After some back and fourth, GM finally bought back the LT for what we paid for it, and we purchased a 2015 Chevy Suburban LTZ that was manufactured in January 2015. It was manufactured 1/7 and we picked it up on 1/12. We drove it around for 3 days… There was no Vibration and No buffeting at all. We have driven it 700 miles home and have roughly put another 600 miles more on it. There is still no buffeting and no vibration at all. It drives like a dream!!!!! I will also add that there is no "low hum" in the LTZ when it is in V4 mode either, like their was with the LT. With the LT you could feel and hear when the vehicle went back and fourth between V4 and V8. With our LTZ the switch is so quiet and subtle, that you cannot tell if it is in V4 or V8 unless you look at the dash. We are very thankful that our dealer was so involved. They were the ones that made the GM Engineer come out to try to fix the vehicle and they are the ones that went to bat for us and got GM to pony up the money to purchase the vehicle back. We would not have gotten the results that we had, if it had not been for our dealer. I would also like to make a comment about the post on here about it being the ANC (Active Noise Cancellation). The LT did not have the ANC yet we still had the buffeting issue. The ANC does not come standard on the LTZ it is something that has to be added. The LTZ we have now does not have the ANC either. So I am not sure that the ANC is the whole problem. I would think if there is a "gap that shouldn't be there" behind the sunroof that could possibly be letting air in, that this may effect your ANC trying to compensate for the problem, making the buffeting worse. Just a thought. From speaking with the GM Engineer, he didn't come right out and say it, but GM knows there is a problem. I think they have fixed it in the manufacturing process (hence the reason the LTZ manufactured in 1/7/2015 does not have the issue), but I don't think they have figured out a fix for the vehicles currently on the road, as my guess there is more than one component causing the buffeting.

Thank you for your info!

With all do respect to everyone on this thread....I don't care if you are having a problem or not we need to be respectful of anyone and their input. There are some that have the issue and some that don't. I know I joined the thread because we have the issue and (at least what we have been told) that GM doesn't know exactly what is causing it or how to fix the problem yet. Nor do I like the fact that my $65,000 car is being taken apart to "try and see if this works" to fix my problem. I am hopeful that by being on this thread we can get some input on what to do to fix the vehicle. So everyone BE NICE!!!!! I will say, we have the Suburban, but in driving different vehicles on the dealers lot while trying to see if others replicated our issue, the buffeting & vibration was more pronounced in the Suburban than in the Tahoe's we drove. The Tahoe's had it, but not as bad. (Unfortunately Tahoe is too small for our family.) We drove 4 of each with all trim levels. We have also driven a Cadillac Escalade ESV(long version) and felt it as well. They did not have a Escalade(short version) on lot for us to compare it to. So wondering if length of vehicle makes problem worse? ANON2015- Since you are in the acoustics industry- I would like to know what equipment/machine you use to test for the buffeting. My whole point in asking is that we are scheduled to meet with GM Engineer in a few weeks and in knowing this information may be able to request the testing(if they don't do it on their own already). Also, you stated you have two vehicles that do not exhibit the vibration or buffeting, what is the manufacture date and manufacturing facility? If I can get a GMC Denali manufactured on "X" date from "X" factory and it doesn't do it, I would upgrade in a heartbeat to alleviate the problem and have a vehicle my family can ride in for more than an hour and not get a headache. Because at this point we are considering a 2014 or different brand. Thanks.

We are not the only Suburban with the problem, our dealer mentioned to us that they have had several that they are dealing with that have same vibration issue (not sure about others and buffeting or at least they haven't mentioned it). Our Service Manager even agrees that there is some sort of problem. We notice the problems as soon as we got it on smooth highway and up to75 mph after purchasing. Dealer was closed the next day so we took the vehicle back to dealer on day 2 with 85 miles on it. Thought it was a tire balance problem, so they balanced the tires. Didn't fix it. We literally had to drive home 60mph on a 75 mph highway the whole 10 hours home. Heard the buffeting at speed of 40-65 mph, but didn't think much of it until we were on our 650 mile drive home & had to stop 3 hours into trip with ear pain pressure & headaches from buffeting. Since then we have made the 10 hour trip 4 times and every time we end up having to stop with severe headaches or kids throwing up from ear pressure/pain. At this point it has become a health hazard to our family to drive it any more than an hour at a time. My husband has a 2009 GMC Sierra and it rides better than this thing! It was manufactured in Arlington TX with date of 8/2014. Since we bought it in September we have had it at dealer 6 times and to a tire shop with Hunter Road Force Balancing Machine 4 times. We go back in a few weeks to meet/ride with GM Engineer. I'lll let you guys know how that goes. Sad thing is, we really love the car. It it the perfect size for our needs and the interior is quite plush. However it is a useless vehicle if you cannot drive it on the highway at highway speeds with out it shaking off the road or getting headaches and ear pain. I would be happy to order another one if I know 100% that the vibration and buffeting problem has been fixed. I have some hope considering there are a few on here that have received vehicles that don't have the problems. We also have the trailering package.

LT 5.3L V8 Ecotec3 Sun, Entertainment, & Destination Package Premium Ride Suspension Not sure about Noise Cancelling Bose Preimium Audio Pwer Lift Gate, Lane Departure Warning, & Forward Collision Alert, Auto Start 2nd Row Bucket No Roof Rack Crossbars 2 Wheel Drive 22" (but, its not the tires. They have put 2 different sets of 18, 2 different sets of 20's, and 4 diff sets of 22' and there was no difference in vibration or buffeting. Trailering package

We have the Suburban and are having a severe buffeting issue as well as severe vibration at speeds of 65-85mph.

Glad to have found this! We purchased a 2015 Suburban LT Labor Day weekend and are having the same issue of the buffering noise, but also a terrible vibration at almost all speeds. The 3 times we have driven on long trips I have gotten terrible headaches, and on the last trip had to lay down in the back it was so bad. We have taken it to the dealer now 5 times and they cannot figure it out. (The first being the day after we bought it.) The service manager says he feels it & hears it, but can't find a fix. At first they thought it was the rims since we have 22's, but we put 4 different sets of 22's, & 1 set of 20's and the problem was still there. We even drove another suburban on the lot and it did the same thing. At this point it has become a health hazard. Not sure what to do from this point on!