Information on Vibration Analysis and Diagnostic – 2014-2015 GM Trucks

[Clarkie]

The issue I was having was a vibration felt in the driver's seat and in the truck cab. It only happened in V4 mode at low RPMs. This would be from 1000 t0 1200 RPM. It started as an intermitant problem and slowly got worse. It always seemed to appear between 60 and 70 kph but would appear at lower speeds as well. The service techs that drove the truck felt it could be heard as much as felt inside the cab of the truck.

[FrankDaTank]

The issue I was having was a vibration felt in the driver's seat and in the truck cab. It only happened in V4 mode at low RPMs. This would be from 1000 t0 1200 RPM. It started as an intermitant problem and slowly got worse. It always seemed to appear between 60 and 70 kph but would appear at lower speeds as well. The service techs that drove the truck felt it could be heard as much as felt inside the cab of the truck.

I am having almost the same exact issue except mine will do it for a whole day then the next day be fine.

I have a 2015 silverado 1500 Z71 LT2 with about 45K miles on it.

When this is happening I also noticed that at a stop with the truck in gear the whole thing will rumble and goes away when you take it out of gear (either park or neutral). It also starts violently during this period and goes away the next day too.

 

I read a TSB about a torque converter clutch pressure valve spring either breaking or wearing out causing a similar issue on the first series of AFM vehicles but was told by the "expert technicians" at my local dealership that they thought it was a wheel bearing

 

I will not be replacing the wheel bearing because there is no way that it is causing it.

 

Anyone ever replace such a spring in their transmission?

[FrankDaTank]

I am having almost the same exact issue except mine will do it for a whole day then the next day be fine.

I have a 2015 silverado 1500 Z71 LT2 with about 45K miles on it.

When this is happening I also noticed that at a stop with the truck in gear the whole thing will rumble and goes away when you take it out of gear (either park or neutral). It also starts violently during this period and goes away the next day too.

 

I read a TSB about a torque converter clutch pressure valve spring either breaking or wearing out causing a similar issue on the first series of AFM vehicles but was told by the "expert technicians" at my local dealership that they thought it was a wheel bearing

 

I will not be replacing the wheel bearing because there is no way that it is causing it.

 

Anyone ever replace such a spring in their transmission?

http://gm.oemdtc.com/3465/vibration-shudder-or-roughness-while-driving-at-low-steady-speeds-in-v4-mode-2011-cadillac-chevrolet-gmc#more-3465

 

This is the TSB I mentioned.

[Rolling Thunder]

http://gm.oemdtc.com/3465/vibration-shudder-or-roughness-while-driving-at-low-steady-speeds-in-v4-mode-2011-cadillac-chevrolet-gmc#more-3465

 

This is the TSB I mentioned.

 

But it says for "2011 Cadillac Chevrolet & GMC." Is it still relevant for later?

Edited April 7, 2017 by Rolling Thunder

[FrankDaTank]

 

But it says for "2011 Cadillac Chevrolet & GMC." Is it still relevant for later?

It perfectly describes the issues I have been experiencing.

 

The 15's have a TCC solenoid so I figured it would be worth mentioning.

[2016 All Terrain X]

I have a 2016 GMC Sierra All Terrain X. I have the same vibration issue that started almost immediately after purchasing the vehicle. It's been in the dealership four times and is no better than when it first started. The reason they are shimming the motor mounts is the change the frequency of the vibration so you don't feel it as much. They hook the vibration meter to a bolt that holds the seat down and shim away until the vibration lessons. Problem with this is it comes back because the root cause was not corrected. Most mechanics nowadays are only capable of remove and replace. If the computer does not tell them what's wrong they have no clue how to troubleshoot. Still having a problem and I'm getting ready for a fifth visit to the dealer. The way I see it is that there is the possibility of three different things that could be causing this. An air leak, a vacuum leak or an electrical short. If it's an air leak or a vacuum leak it's not very big. At idle or slightly above idle the leak is a larger percentage of the total air and fuel coming into the system. When RPM's are elevated the leak is a smaller portion of the air and fuel coming into the system and is virtually undetected. I also think it might be a problem with the way the vacuum system is setup. The system measures vacuum inside the manifold as well as out the manifold. If one system is using gauge measurements and the other is using absolute measurements it could cause problems at low RPM's. A gauge measurement is a linear equation and an absolute measurement is a quadratic equation. The bottom line with this is that the small differences in the method of measuring would cause problems at low RPM's but would be disguised at high RPM's due to the increased volume inside the manifold. The third issue of it being electrical would almost certainly cause the check engine light to come on so I have not gone down that road yet. Anyone else have luck getting their rough idle fixed?

[lloydsmale]

On ‎4‎/‎26‎/‎2017 at 3:34 PM, 2016 All Terrain X said:

I have a 2016 GMC Sierra All Terrain X. I have the same vibration issue that started almost immediately after purchasing the vehicle. It's been in the dealership four times and is no better than when it first started. The reason they are shimming the motor mounts is the change the frequency of the vibration so you don't feel it as much. They hook the vibration meter to a bolt that holds the seat down and shim away until the vibration lessons. Problem with this is it comes back because the root cause was not corrected. Most mechanics nowadays are only capable of remove and replace. If the computer does not tell them what's wrong they have no clue how to troubleshoot. Still having a problem and I'm getting ready for a fifth visit to the dealer. The way I see it is that there is the possibility of three different things that could be causing this. An air leak, a vacuum leak or an electrical short. If it's an air leak or a vacuum leak it's not very big. At idle or slightly above idle the leak is a larger percentage of the total air and fuel coming into the system. When RPM's are elevated the leak is a smaller portion of the air and fuel coming into the system and is virtually undetected. I also think it might be a problem with the way the vacuum system is setup. The system measures vacuum inside the manifold as well as out the manifold. If one system is using gauge measurements and the other is using absolute measurements it could cause problems at low RPM's. A gauge measurement is a linear equation and an absolute measurement is a quadratic equation. The bottom line with this is that the small differences in the method of measuring would cause problems at low RPM's but would be disguised at high RPM's due to the increased volume inside the manifold. The third issue of it being electrical would almost certainly cause the check engine light to come on so I have not gone down that road yet. Anyone else have luck getting their rough idle fixed?

this seems to be the core problem were dealing with. Gm is tight lipped about what is causing all this problems. they don't even tell there dealership service depts. it even exists. I know guys personally in the service dept at my dealership and they said Gm has sent no bulletin on this so they don't know where to start. they said Gm acts like the problem doesn't exist. All they tell them is theres an expectable level of vibration which is total bs. A 47k truck should NOT vibrate. I think gm is sitting back figuring if they admit to it it will cost them major money to fix them all and that a good many will just live with it when there told its within guidelines or get so disgusted that they trade the truck off on something else. that and a good many aren't mechanically inclined enough or pay attention enough to even notice it. If I never drove above 60mph I wouldn't have noticed it either. New wheels and tires cured mine but for how long? It obviously too doesn't cure everyones. First time a tie rod end falls apart from premature wear at 30k and kills someone gm might actually do something. Just hope its not you that is that person.

[Black Denali Canada]

?‍♂️


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[Obscenejesster]

Prior to my last post I had visited my dealer suggesting that my 2015 had a transmission issue based on information I had received onn this forum. They quickly dismissed my therory and I felt I had reached the end on my rope. As suggested by a local transmission shop I added a transmission anti shuddering additive. This was done with the permision of the GM dealer I was dealing with. Feeling there was no hope in getting my truck fixed I began shopping for a new truck. I had a truck selected and then I contacted GM customer service hoping for some finacial assistance to replace the truck that "could not be fixed". To my suprise this representative was very helpful. She took all my information and then said she would call back in a few days. In a few days she called back and asked me to return to the dealer for a attempt to repair the truck. They had the truck for one day and too my suprise the truck appears to be fixed. It may not be perfect but it is more than 95% better and to this point I am satisfied and will no longer be looking to replace my truck.
 
The issue with the truck was a vibration in the exhaust system. The repair was to replace the exhaust from the cat convertor back. There appears to be a back pressure device in the system. In the new system this device has been moved from downstrem of the muffler to in front of the muffler. This has solved my complaint.

Same exact issue I had except that I fixed mine with a Range AFM Deleter. Now that it never goes into V4 mode, I no longer have this problem.

Couldn't stand V4 mode anyway. Honestly, I'd rather have a turbo charged 6 cylinder at this point.

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[JTDowdy]

Anybody have a workable document or link they can share?  I am unable to open and could really use some more knowledge on this subject.

[flyingfool]

have you guys tried the walnut blasting the intake valves to remove build up and improve airflow? 

you might want to run a boroscope down the manifold see how bad your valves are slugged up....

 

 

DYI Walnut Shell Blasting SS 3-27-13.pdf

[SS502]

Folks, we can all post on these forums until the cows come home but it won't mean squat except to aid in the venting process...report ALL problems so there can be a collective information data report that can actually be reviewed and possibly put pressure on any manufacturer for a fix.

 

https://www.nhtsa.gov

[Richard Gutierrez jr.]

2018 siverado,at 5,000 miles it developed a strange noise,its inconsistent but annoying, with many different opions on cause,it sits with the dealer 45 minutes away.they asked me to come get it until I hear it again,I dont want it back until its fixed! I hv.a loaner but standing my ground.noise sounds like its comming from the front.

[Rick Murphy]

https://vibratesoftware.com/2016/12/26/nvh-app-the-chevy-chevrolet-shake-no-one-fix/

[Borntorun]

I have a 18 Sierra Crew Cab I notice a vibration when deceleration. I also own a 2017 Corvette and on the Corvette Forum C7 section there is a lot of info with vibration when in or entering V4 mode. There is mention of Range Device / AFM Disabler that keeps vehicle from entering V4 mode. My Corvette didn’t have any problems with V 4 mode.But I bought Range Device back in 17 to keep Corvette from entering V4 mode as a preventative / peace of mind thing.  In November after putting car in winter storage I pulled device out of car and installed in 18 Sierra. I thought lets see if this will help with hard shifting / vibration and engine seeming to run rough when entering V4 mode. It appears by blocking V4 mode it has eliminated or reduced the hard shifting / vibration that I don’t notice it. Seems to have removed my concerns. Device probably didn’t solve problem. But by stopping my Sierra from going into V4 mode it has made driving 18 Sierra better ! 

If anyone wants more info on device.google Range Device or check out

www.rangetechnology.com 

Edited January 14, 2020 by Borntorun