Vibration on brand new '22 AT4x

Snowstormer · Apr 10, 2023

Monday 4/10/22 - Took delivery last Thursday and was very happy with my new truck, it had 8 miles on the odometer. After getting on the highway at speeds around and above 60mph I noticed a bad vibration coming from the bottom of my seat which permeated throughout the entire truck. I checked the air pressure and also checked to make sure I had not "thrown" a weight from the wheels. Everything checked out. I took it back to the dealer today and explained to them what I was experiencing. I thought they would simply rebalance the tires and I would be back on the road and on my way to my tint shop. At this particular dealership, they have a glass overview of the mechanic shop so I watched the tech pull my truck in and then back out for a test drive which gave me the idea of using the MyGMC app to track where he was driving the truck. I noticed that he didn't take it on the highway which is where the vibration is most noticeable. The tech came back after about a 15-minute drive and I promptly left the waiting area and went to the counter so I could listen in on what he would say to my service advisor as he did not know me to be the owner of the truck he just drove. To my surprise, he comes right in and blurts out to the SA that he believes that the truck has flat spots in all 4 tires. He goes on to say that the truck shakes pretty bad and that he had dealt with another truck last week with the same issue but wasn't as bad as mine. The SA asked if the truck is driven more would it work itself out (my truck only has about 250mi on it now)? The tech said that he didn't think so, he referenced a GM bulletin which states that after a certain amount of time, the flat spots become permanent. They then looked up my VIN and confirmed that the truck had sat on a Detroit holding lot for approx. 8-9 months waiting for missing chips. The SA then mentioned to me that I needed to drive the truck to at least 1,000 miles before GM would do anything per GM policy. I told him I was not comfortable doing that as the truck was giving me a literal headache when I took it up to highway speeds. He suggested that perhaps they could drive it to 1,000 miles for me, I said I do not agree to that either. Eventually, they put me in a loaner and are trying to figure out how to resolve this issue.
I wanted to let others know about this as I had another brand new car that I purchased last year for my rental fleet that was doing the same thing and the dealer rebalanced the tires 3 times which did not completely resolve the issue. Both vehicles were high-end models and both sat while waiting for chips. Just want others to be aware as it's pretty easy to check approx. how long your car/truck has been "sitting" by looking at the MF date and comparing it to the actual delivery date. I think this is a lesson learned for me regarding low-mileage vehicles that perhaps the average person wouldn't always think of. To the dealer's credit, they admitted that the truck shouldn't ride like it was and they didn't try to make me feel like it was all a figment of my imagination. That said, they are trying to figure out if GM is going to cover the cost of the tires or the dealership. I have my thoughts but I have decided to see what happens.

I will provide an update once it is resolved.

Updated: The dealer paid for new tires. I opted to go with Nitto's and wow what a difference! Don't recommend the stock tires at all.

RugbyRef · Apr 11, 2023

Good luck @Snowstormer! Keep us posted.

roy826ex · Apr 11, 2023

My 23 has a slight out of balance feel at around 73-75 mph. I just figured it was an out of balance wheel. My build month was 12/22 and I took delivery 1/23/23 so my truck didn't sit anywhere any period of time. But it sits in a garage daily and never gets used except once a week if I drive it at all then. I work from home and have no where to drive daily. I only have 998 miles on the truck and it had 8 miles on it when I took delivery.

Snowstormer · Apr 11, 2023

roy826ex said:
My 23 has a slight out of balance feel at around 73-75 mph. I just figured it was an out of balance wheel. My build month was 12/22 and I took delivery 1/23/23 so my truck didn't sit anywhere any period of time. But it sits in a garage daily and never gets used except once a week if I drive it at all then. I work from home and have no where to drive daily. I only have 998 miles on the truck and it had 8 miles on it when I took delivery.

You might want to look at getting a set of these then: https://www.amazon.com/s?k=flat+spo...fix=flat+spo,aps,76&ref=nb_sb_ss_ts-doa-p_1_8

These are probably cheaper than new tires....

Snowstormer · May 5, 2023

Resolved: Dealership paid for brand new tires.

pinebaron · Nov 22, 2023

I have the same issue with my new 2024 GMC Sierra AT4X AEV Edition almost right off the dealers lot (I was 100 miles away on my way home 300 miles away). Despite the fact a local dealer confirmed 3 of 4 tires failed Roadforce tests, GMC refused to pay for replacement tires and insisted on a picoscope tests which according to them ruled out the tires. At my own expense, I changed all five tires from Wrangler MT to Mickey Thompson Baja Boss 305/70 R18 and they helped somewhat but the issue has not been resolved. Vibrations up the seat and right through my head occur when driving on highways at any speed especially when the freeway/highway asphalt is not 100% smooth and thats most roads. GMC have failed to acknowledge the issue and won't do anything to help resolve it saying this is normal for this truck. Having changed all tires, my attention is now focused on the new DSS Multimatica shocks. One minute the truck will be riding smooth then it starts vibrating at approximately 2 vibrations a second, it does not sway front to back or left to right, just up and down and the ride gets intolerable very soon. Other areas could be a loose engine mount, with the heavy Duramax 6.6L V8 up front, or the very heavy duty drive shaft but I'm only guessing on how to fix this $130k lemon. Any ideas?

Snowstormer · Nov 22, 2023

pinebaron said:
I have the same issue with my new 2024 GMC Sierra AT4X AEV Edition almost right off the dealers lot (I was 100 miles away on my way home 300 miles away). Despite the fact a local dealer confirmed 3 of 4 tires failed Roadforce tests, GMC refused to pay for replacement tires and insisted on a picoscope tests which according to them ruled out the tires. I changed all five tires from Wrangler MT to Mickey Thompson Baja Boss 305/70 R18 and they helped somewhat but the issue has not been resolved. Vibrations up the seat and right through my head occur when driving on highways at any speed especially when the freeway/highway asphalt is not 100% smooth and thats most roads. GMC have failed to acknowledge the issue and won't do anything to help resolve it saying this is normal for this truck. Having changed all tires, my attention is now focused on the new DSS Multimatica shocks. One minute the truck will be riding smooth then it starts vibrating at approximately 2 vibrations a second, it does not sway front to back or left to right, just up and down and the ride gets intolerable very soon. Other areas could be a loose engine mount, with the heavy Duramax 6.6L V8 up front, or the very heavy duty drive shaft but I'm only guessing on how to fix this $130k lemon. Any ideas?

PB: IMO opinion I don't think it is the truck's suspension or engine mount. My truck drove so differently from before to after the tire issue you'd think it was a completely different truck, it went from riding like a piece of junk to almost car like. That said, it is most likely one of two things:
1. Improper balancing - did they confirm that they mounted the tires on the rim properly, did they confirm the tires didn't need to be rotated on the rim? Roadforced before and after? Reconfirm tire pressures?
2. You have a bad tire. Even though they may be brand new this is possible. I also saw some mixed reviews on the MT Boss since it is a fairly new tire. I can't recommend the Nittos highly enough!

One thing you could do if you have checked everything else, is rotate the wheels/tires one side from front to back to see if the vibration changes...if it feels exactly the same then do the other side.....if it stays exactly the same after that then I would start to look at the truck.

Keep us posted.

-SS

pinebaron · Nov 22, 2023

SS: What I failed to mention, the dealer also tried a different set of larger wheels and tires of another different truck on their lot however the problem persisted, hence I suspect its something else but point taken.

My new tire guy balanced all the new Mickey Thompson tires/wheels as expected. I have not subjected them to a roadforce test at the dealer yet. What I can do is move tires from front to back since the tire guys did not change the wheels around while replacing tires, I'll do that this morning. I'll keep you posted.
Please keep the suggestions coming in, thanks.

pinebaron · Nov 22, 2023

moved wheels front to back and vice versa. Will be heading out around noon and will be able to tell if it made any difference at all.

pinebaron · Nov 23, 2023

Having done that, it did not improve anything, almost felt it made things worse. I think if still focusing on a defective wheel/tire, I need to replace each with the spare, then test.