Buffeting / Vibrations/ cabin ear pressure

[sealandsky]

A couple of weeks ago I drove a a 2018 leftover 6.2l RST and thought it was a qualified hit. A few days later I drove a Denali to see another take. I thought it was a more mild-mannered and chromed out RST in comparison. I preferred the more understated blacked out look the the Tahoe RST. My main concerns at that point was the expected mileage penalty for the 6.2l v8 on a heavy BOF truck versus a more fuel efficient crossover.

I took the family out today to drive the RST again thinking we had narrowed our new car search. I'm looking for an SUV with some performance that can haul the family and our gear on road trips / vacations. I had a much more keen eye and ear for today's drive and of course the wife would be looking for problems too.

While still in the dealer's lot rolling along at 10mph-15 mph we both experienced buffeting that only got worse as we took the truck up to 45mph-50mph on the road. Absolutely terrible. I cant believe I didn't notice this on my initial test drive (in the exact same truck), nor anything like it in the Yukon Denali. Today it was bad enough to make me feel nauseous. Of course, the sales guy sitting in the 3rd row claimed ignorance at first and then began to blame the air vents in the 3rd row - I wanted to punch him for that last one.

Of course I knew what it was immediately having been reading this forum for the last two weeks and having read the GM TSB; I had hoped this was an issue mostly with the 2015's....but I guess not.

So disappointed.

Just making sure that one of the windows was not open a bit?

 

[mikeb3408]

What is the new part number for the torque converter to help with the sound issues.

Also can anyone tell me more about disabling the AFM/ V4 mode? Is that something easy/recommended to do?

 

[Prospect62]

As you all can see I'm relatively new to these trucks but from what I've seen and read, this issue has been traced to roof bows not being properly sealed to the roof panel at the factory. Every GM SUV in this line from 2015-2020 *may* end up with the issue. Some do, some do not. Luck of the draw as some have said.

The "fix" for GM is to remove the headliner, re-seal the roof bows to the roof panel and cross your fingers. I don't think AFM, torque converters or tires are the cause of this - although vibrations caused by those factors may contribute to exposing it.

 

[gat0r]

As you all can see I'm relatively new to these trucks but from what I've seen and read, this issue has been traced to roof bows not being properly sealed to the roof panel at the factory. Every GM SUV in this line from 2015-2020 *may* end up with the issue. Some do, some do not. Luck of the draw as some have said.

The "fix" for GM is to remove the headliner, re-seal the roof bows to the roof panel and cross your fingers. I don't think AFM, torque converters or tires are the cause of this - although vibrations caused by those factors may contribute to exposing it.

restabilizing the roof bows is not the ultimate fix. plenty here & on other forums have verified that.

it seems to be more of a few things together...that may fix the issue.
however that is also not that case for some. GM does not a true fix for it still, for anyone that does have the issue.

it will be an experiment & a journey w/ GM & the dealer (as GM still tries to remove their head from their sphincter) using the list of items listed in this thread.

 

[Prospect62]

restabilizing the roof bows is not the ultimate fix.

That's why I said it was GM's fix, and not the "ultimate" fix.

It does seem logical - the roof panels on these things are enormous sheets of metal, and not put together like they have been in previous generations of trucks but rather employing a new method for assembly relying on glue essentially. Once they come loose and start harmonically vibrating, it's going to cause these symptoms.

 

[Jeramia]

I get the buffeting when the rear windows are down on my 15 Tahoe I also get it with my 05 Tahoe, And I get a slight vibration when it's in the V4 mode. Other than that, it's a great truck.

 

[JB11]

I'm thinking about buying a 2020 Custom, is this buffeting some I'll notice on this first test drive or does it develop over time?

 

[gat0r]

you'll notice on test drive, if its there.
make sure to try as many road types as possible & speeds btwn 25-75 (or so)

good idea to bring some other folks w/ you. as some have more sensitive ears than others.

 

[JB11]

Thanks, I was planning on buying a 2020 versus waiting for the next generation. I thought the 2020 would have all the issues resolved. I never buy a first year run of any make/model and nowadays with all the technology it may take 2-3 years to work out the bugs.

 

[Prospect62]

Thanks, I was planning on buying a 2020 versus waiting for the next generation. I thought the 2020 would have all the issues resolved. I never buy a first year run of any make/model and nowadays with all the technology it may take 2-3 years to work out the bugs.

The way I understand it, a 2020 model would be no less likely to have the issue than a 2015. The issue is in the particular way the roof is attached to the vehicle, which hasn't changed at all since the first truck on this platform was built. As suggested, you'd probably notice it right off the bat on a test drive - but I'd say it's certainly possible for the issue to "develop" as the truck ages.

I count myself lucky as my 2016 Suburban does not have the issue at all and I'm at 65,000 miles.