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Posted
I'm not familiar with this website, but thought this was worth posting.

 

 

Always worth posting. Looks like GM got most of the info in this document off this thread by finally compiling data based off customer input and dealers doing what they can to mitigate the issues. GM mentions V8 to V4 (AFM) transition, ANC, mics, amp, speakers, exhaust, powertrain, etc, issues talked about in length on this thread. Some suggestions on the document won't work, customers on this thread already tried them. This document also suggest this issue caught GM off guard, don't know how though. Just like a customer could identify these issues, a highly trained factory tech should have also noticed the issues. Afterall, they don't just make a truck and put it on the street without testing. However, there is one piece of new info for owners of the 5.3L engine (probably Chevy), engineers are working on improvements to the exhaust system, which may assist with improvements with the 6.2L engine.

Posted

***UPDATE***

My dealer has now had my vehicle another full week. As I stated in my previous post, my issue was supposed to be escalated to a specific engineer and that the next step was to get an entire new rear end housing. Needless to say, after a week, this did not happen.

My Service Manager (SM) told me GM required him to do a multitude of test with a Pico scope (basically a device that measures vibrations). During the test they found the following results:

The worst of the vibrations were at 53 MPH and the vibrations measured 29.7hz with a 49ng at that speed.

The Pico scope also reported the vibration was coming from the driveshaft. They measured the driveshaft to the ‘nth’ degree and did not find anything unusual. Then they focused on the head end connection and the rear end connection of the driveshaft. They did several measurements and found the rear pinion flange to be warped. It was measuring .27mm at the top and .47mm when rotated (I am not 100% for sure what this means, but I assume it should be the same measurement). My SM stated the pinion flange looks to be cast incorrectly causing the flaw in the design.

Basically, all of the testing took a full week and a new pinion flange was ordered on Friday and arrived yesterday afternoon. If everything goes as planned, including more test after the new pinion flange is installed, I should be able to test drive the vehicle this afternoon to see of this corrected my problem.

I hope this solves both the vibration at 53 MPH and the buffeting at 43 MPH. I will report back at let you know my findings.

Posted

I have the same issue with the Tahoe 2015. Just got it a week ago and since the start I experianced a vibration at 66 mph which let me feel I am inside a plane. I went to the agency and they said send it to the workshop and ask them to check the tires !!!!

Posted (edited)

Feel like an idiot for not doing more research into the ANR prior to my purchase. During summer trip we rented a semi-loaded GMC Yukon XL SLT in South Dakota and put 700 miles on it. I didn't like the 5.3I with 3.08 rear. Just closed on a 2015i Yukon Denali XL 4X4 two days ago, May 20th build per the GM representative.

 

If I had read these threads I would have NEVER bought this vehicle. Broke my own rule: "Thou shalt NEVER buy 1-2 years into new gen vehicles". I can only pray this is not going to be the most expensive mistake I ever made. My 2011 Sub LT 4X4 was bullet proof. :(

Edited by Scurvey
Posted (edited)

Been driving the 2015i Denali XL around in the recommend ranges and don't have any pressure or booming issues yet. Truck currently has 400 miles on it.

 

For what the vehicle is (full size family hauler) the ride is absolutely amazing, however it is a completely different type of ride from the last generation of what I call "floaters" (2007-2014, very loose/floaty/drifting rides). If you have ever spent a fair amount of time in a BMW or an Audi you will be familiar with the type of ride I am talking about. Its more "German" than "American" in terms of how the road surface communicates back to the driver. The truck is a 4x4 and has the 7500 GVWR package so that probably does stiffen up the ride a bit.

 

If you are coming from the previous generations of vehicles expect a dramatically improved but completely different driving experience. You need to test drive this car extensively on various road surfaces and speeds to understand its handling.

Edited by Scurvey
Posted (edited)

 

Are you experiencing any shaking or vibration?

 

Nothing abnormal. I am running 22 inch with painted inserts (Q7M code). 700 miles was in a SLT with 20 inch aluminum wheels. Ride is probably a touch firmer with the 22 inch setup but its hard to tell the difference.

 

Put another 50 miles on the vehicle today driving freeway / back roads / stop-and-go traffic. My litmus test for shaking and vibration is too look over at the passenger headrest and see the amount of vibration. Seat attachment to a frame is essentially a lever with a mechanical advantage. Today I could hardly notice any vibration in the headrest. If you take a ride in my 2013 F150 Off-road 4X4 you will see the headrest vibrating at most speeds. I want to reiterate is that if you are expecting to just "float and glide" across the road like some sort of maglev train that is not what this truck does. It has excellent smooth ride quality but still lets you experience some of the surface conditions. I am fine with that. If you have ever driven a Lexus LS400 you know what I am talking about.....ride so refined and disconnected that it drives you to tears with boredom. I don't want that please.

 

There have been a 1 or 2 oddball shifts on the transmission but I don't really think about transmissions until the break-in program has completed. I don't plan on doing anything with the 4x4 transfer case until well after 500 miles.

 

Regarding quality control, just a couple of minor issues (I can always find something wrong with any vehicle). Interior guy forgot to clip in the drivers side front leather attachments. I simply grabbed them and clipped them in as designed. The only way you would see this is to look under the seat. Sunroof weather proofing strip was sort of hung up for about 1/2 inch. Simply straightened it out with a credit card.

 

Absolutely love this truck so far and so does my wife.

Edited by Scurvey
Posted

You know what Scurvey, that is good news about your truck and I could say the same about mine. But this thread is about folks that are experiencing vibration, shaking, pressure and buffeting with the GM fullsize SUV. Start another thread titled something like "Absolutely Love this Truck", your previous comments would read very well there. Been hanging around this thread since page one, just a constructive observation.

Posted

...just a constructive observation.

 

Taken the wrong way, the info you were posting would get more comments on a different thread, added info should at least be somewhat on point. Driving my truck since Mar 14 there is a laundry list of good things I could say about it, on another thread.

Posted (edited)

My point: Natural ride characteristics of the vehicle characterized by some as "normal" will be characterized by others as "unacceptable vibration". Moving along!

Edited by Scurvey
Posted

Wanted give an update. I have test drove the latest Cadillac, Suburban and Yukon. All with the intermin model build, all have the same noise. It sounds like a window is down. Some are worse than others, but they all have it. We almost bought a new Yukon XL last weekend, but we backed out. The vehicle is so nice and fits my family of 6, but I just can't get past the feeling in my head. Crazy that we would even consider doing it all over again, but the truck is perfect, other than the pressure. As of now, they have not fixed the issue, or have a fix in the works. Does anyone have an inside track on when the 2016's come out?

Posted

Is the pressure different than the shaking and vibration, or does it all occur together? One individual said that you could actually see the headliner shaking? Is this the same issue you are experiencing on your test drives?

Posted

So... May be a dumb question but do you guys think putting bigger wheels and tires can make it worse if you believe it's tied to the rear end problems? I went from factory SlT 20s to a 22 with a 305/40 and it seems the rear end rumble under load and corresponding ear pressure is much worse. Thoughts?

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