Shake or Vibration Issues

[Bayou_Vista]

Add me to the list of new truck owners with the vibration problem. I had not read or heard about these problems prior to purchasing my 2015 Sierra 1500. I took it to the dealer with 90 miles on it to report the vibration. They asked me to drive it for 500 miles and bring it back which I did. They balanced the tires which didn't help. Next up is force balance on Tuesday. This thread is very helpful. I agree with post right above this one that we need to forward the Fox report to anyone that you can asking them to look into the truck problems as well.

[southern_sierra]

This is the first truck out of 17 that I have ever had to have the tires road forced balanced. This goes right along with the frame and body mounts being to stiff and not absorbing any mild vibrations so the wheels have to be perfect not to feel anything.

[paxtonman]

My small town dealer seeing problems too. And I'am a crusty old farmer.

 

No offense meant Southern!

[southern_sierra]

 

No offense meant Southern!

And none taken Paxtonman

[jlozzi]

I would like to just let all of you Silverado 1500 owners know that I to have had a 2015 that was shaking right away when I left the dealer. I soon found this thread after but it was to late for me.

 

I fought with GM and the deal over this for more than 3 months and I finally got them to give me "trade assist" to get out of the 2015 that was shaking so bad that you would wear your coffee if it was in the console.

 

GM came up with $6500 in trade assist to get me to where my payments were for the `15 with 2500 miles that I was having issues with shaking. I ended up test driving 3 2016 trucks before I found one that didn't shake going down the road at the magic number of 74 mph.

 

If you are buying a new 1500 take it for a test drive on the highway! if it shakes at 75 don't even bother buying that truck, ask to take another for a ride.

 

It to me seems really random and honestly it seems like it is something in the transmission causing this. From me taking all these trucks for rides the last one that doesn't shake shifts totally different then the rest.

 

Good Luck all.. Don't delay if yours shakes, it wont go away, keep hammering on the dealer and tell them you want to get out of it and they need to come up with some money to help you.

Edited January 3, 2016 by jlozzi

[fireaxxe]

I have dealt with a lot of vibration issues on various vehicles. This truck absolutely stumps me. I had a slight vibration at about 65-76mph or so that was consistent and was solved by rotating and balancing the tires. Discount tire in this area does this for free.

 

I also have a vibration during deceleration from 50-40 mph ONLY WHEN IN GEAR this is a tricky on but I feel it mostly in the steering wheel and the pedal so I am thinking motor mounts.

 

I also have a high speed vibration (70-76mph) when truck has been sitting for awhile and the temps are cold 40F and below, its almost like the tires have flat spots, Goodyear 18", or maybe the new hydraulic cab mounts in the rear are too stiff when cold and transmitting more vibrations into the cab, this vibration always smooths out when after about ten miles of hwy driving.

 

On thing that I did do was loosen up the body mounts, and the sweet spot seems to be 90ft lbs of torque when I retighten them and 60 ft lbs on the front two mounts just under the radiator.

 

Took it on a 400mile trip yesterday and it was mostly glass smooth at all speeds. I did notice some strange vibrations that were very subtle when it was in v4 on deceleration and pulling up a few hills when the RPMs were lower, this however was not consistent at all.

 

I was thinking early on that my issue was in the rear end now I am stumped. I read a post that stated this vibration issue is a perfect storm of many design issues causing the truck to not mesh together. The best theory I have heard thus far is that the frame is just too stiff. If this is the case maybe the frame can be dampened by filling the hollow space with some foam or something that absorbs and can dampen these vibrations. I hope GM post a fix for this issue soon.

Edited January 3, 2016 by fireaxxe

[rshad]

I would like to just let all of you Silverado 1500 owners know that I to have had a 2015 that was shaking right away when I left the dealer. I soon found this thread after but it was to late for me.

 

I fought with GM and the deal over this for more than 3 months and I finally got them to give me "trade assist" to get out of the 2015 that was shaking so bad that you would wear your coffee if it was in the console.

 

GM came up with $6500 in trade assist to get me to where my payments were for the `15 with 2500 miles that I was having issues with shaking. I ended up test driving 3 2016 trucks before I found one that didn't shake going down the road at the magic number of 74 mph.

 

If you are buying a new 1500 take it for a test drive on the highway! if it shakes at 75 don't even bother buying that truck, ask to take another for a ride.

 

It to me seems really random and honestly it seems like it is something in the transmission causing this. From me taking all these trucks for rides the last one that doesn't shake shifts totally different then the rest.

 

Good Luck all.. Don't delay if yours shakes, it wont go away, keep hammering on the dealer and tell them you want to get out of it and they need to come up with some money to help you.

 

The only problem I have with getting a new 2016 is first, can you find the options you want and second, my truck road great for the first 600 miles or so so how do you really know that the 2016 you have now will not start vibrating after a few miles are on it?

[paxtonman]

There aren't that many 6.2 Silver trucks out there, that's what I want, and my buyback Sierra was fine for the first 200 miles.

[tonygxp]

I would like to just let all of you Silverado 1500 owners know that I to have had a 2015 that was shaking right away when I left the dealer. I soon found this thread after but it was to late for me.

 

I fought with GM and the deal over this for more than 3 months and I finally got them to give me "trade assist" to get out of the 2015 that was shaking so bad that you would wear your coffee if it was in the console.

 

GM came up with $6500 in trade assist to get me to where my payments were for the `15 with 2500 miles that I was having issues with shaking. I ended up test driving 3 2016 trucks before I found one that didn't shake going down the road at the magic number of 74 mph.

 

If you are buying a new 1500 take it for a test drive on the highway! if it shakes at 75 don't even bother buying that truck, ask to take another for a ride.

 

It to me seems really random and honestly it seems like it is something in the transmission causing this. From me taking all these trucks for rides the last one that doesn't shake shifts totally different then the rest.

 

Good Luck all.. Don't delay if yours shakes, it wont go away, keep hammering on the dealer and tell them you want to get out of it and they need to come up with some money to help you.

 

 

i think it may be in the rear end. of the 3 maybe the one that shifted totally different had a different rear gear or was assembled earlier or later than the others? maybe it is just a matter of an out of spec torque gun upon manufacturing? preload set on the pinion bearing?

like one of the other guys mentioned before.. the tires/wheels have to be 100% on or it exacerbates the issue (imo).. and that's PROBABLY why some that get the balancing see no improvement? the rear is just that far out of spec.. and the cab body mounts, like has been mentioned, are just not in sync with the resonance being created by this powertrain/frame...

it's maddening

 

 

btw, see the definition blow?

 

this is what we are dealing with.. good part bad part it doesn't matter... whatever parts are causing this resonance are more elusive than Keyser Soze lol... sucks.. yes, i can make light of it what else can we do? UNFORTUNATELY there are way worse things in life we have to deal with...

 

 

 

resonance - when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion. The word resonance comes from Latin and means to "resound" - to sound out together with a loud sound.

here's a quick read on frequency/resonance to break it down somewhat.. i equate the cab to the object with standing waves that is being affected by the other object moving.. when it hits 74mph is when the "MUSIC" starts lol

 

 

 

resonance vibration

resonance vibration [′rez·ən·əns vī‚brā·shən]

(mechanics)

Forced vibration in which the frequency of the disturbing force is very close to the natural frequency of the system, so that the amplitudeof vibration is very large.

^^^^^^^^^^ this is the water vibrating in the bottlein the cupholders in a few of those trucks where the owner took video and linked it here.... when the water is just "buzzing" violently that's the spot- the resonance vibration.... our trucks do this naturally just to different degrees, which is where GM is dropping the ball.. they cannot (for most of us) isolate the biggest offender and "fix" that part so that the rest of the naturally occuring resonance vibration goes mostly undetected... it's just different decibel levels....

 

 

Resonance

• Resonance
• Guitar Strings
• Open-End Air Columns
• Closed-End Air Columns

The goal of Unit 11 of The Physics Classroom Tutorial is to develop an understanding of the nature, properties, behavior, and mathematics of sound and to apply this understanding to the analysis of music and musical instruments. Thus far in this unit, applications of sound wave principles have been made towards a discussion of beats, musical intervals, concert hall acoustics, the distinctions between noise and music, and sound production by musical instruments. In Lesson 5, the focus will be upon the application of mathematical relationships and standing wave concepts to musical instruments. Three general categories of instruments will be investigated: instruments with vibrating strings (which would include guitar strings, violin strings, and piano strings), open-end air column instruments (which would include the brass instruments such as the trombone and woodwinds such as the flute and the recorder), and closed-end air column instruments (which would include some organ pipe and the bottles of a pop bottle orchestra). A fourth category - vibrating mechanical systems (which includes all the percussion instruments) - will not be discussed. These instrument categories may be unusual to some; they are based upon the commonalities among their standing wave patterns and the mathematical relationships between the frequencies that the instruments produce.

 

 

Resonance

As was mentioned in Lesson 4, musical instruments are set into vibrational motion at their natural frequency when a person hits, strikes, strums, plucks or somehow disturbs the object. Each natural frequency of the object is associated with one of the many standing wave patterns by which that object could vibrate. The natural frequencies of a musical instrument are sometimes referred to as the harmonicsof the instrument. An instrument can be forced into vibrating at one of its harmonics (with one of its standing wave patterns) if another interconnected object pushes it with one of those frequencies. This is known as resonance - when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion.

The word resonance comes from Latin and means to "resound" - to sound out together with a loud sound. Resonance is a common cause of sound production in musical instruments. One of our best models of resonance in a musical instrument is a resonance tube (a hollow cylindrical tube) partially filled with water and forced into vibration by a tuning fork. The tuning fork is the object that forced the air inside of the resonance tube into resonance. As the tines of the tuning fork vibrate at their own natural frequency, they created sound waves that impinge upon the opening of the resonance tube. These impinging sound waves produced by the tuning fork force air inside of the resonance tube to vibrate at the same frequency. Yet, in the absence of resonance, the sound of these vibrations is not loud enough to discern. Resonance only occurs when the first object is vibrating at the natural frequency of the second object. So if the frequency at which the tuning fork vibrates is not identical to one of the natural frequencies of the air column inside the resonance tube, resonance will not occur and the two objects will not sound out together with a loud sound. But the location of the water level can be altered by raising and lowering a reservoir of water, thus decreasing or increasing the length of the air column. As we have learned earlier, an increase in the length of a vibrational system (here, the air in the tube) increases the wavelength and decreases the natural frequency of that system. Conversely, a decrease in the length of a vibrational system decreases the wavelength and increases the natural frequency. So by raising and lowering the water level, the natural frequency of the air in the tube could be matched to the frequency at which the tuning fork vibrates. When the match is achieved, the tuning fork forces the air column inside of the resonance tube to vibrate at its own natural frequency and resonance is achieved. The result of resonance is always a big vibration - that is, a loud sound.

Another common physics demonstration that serves as an excellent model of resonance is the famous "singing rod" demonstration. A long hollow aluminum rod is held at its center. Being a trained musician, teacher reaches in a rosin bag to prepare for the event. Then with great enthusiasm, he/she slowly slides her hand across the length of the aluminum rod, causing it to sound out with a loud sound. This is an example of resonance. As the hand slides across the surface of the aluminum rod, slip-stick frictionbetween the hand and the rod produces vibrations of the aluminum. The vibrations of the aluminum force the air column inside of the rod to vibrate at its natural frequency. The match between the vibrations of the air column and one of the natural frequencies of the singing rod causes resonance. The result of resonance is always a big vibration - that is, a loud sound.

The familiar sound of the sea that is heard when a seashell is placed up to your ear is also explained by resonance. Even in an apparently quiet room, there are sound waves with a range of frequencies. These sounds are mostly inaudible due to their low intensity. This so-called background noise fills the seashell, causing vibrations within the seashell. But the seashell has a set of natural frequencies at which it will vibrate. If one of the frequencies in the room forces air within the seashell to vibrate at its natural frequency, a resonance situation is created. And always, the result of resonance is a big vibration - that is, a loud sound. In fact, the sound is loud enough to hear. So the next time you hear the sound of the sea in a seashell, remember that all that you are hearing is the amplification of one of the many background frequencies in the room.

 

 

Resonance and Musical Instruments

Musical instruments produce their selected sounds in the same manner. Brass instruments typically consist of a mouthpiece attached to a long tube filled with air. The tube is often curled in order to reduce the size of the instrument. The metal tube merely serves as a container for a column of air. It is the vibrations of this column that produces the sounds that we hear. The length of the vibrating air column inside the tube can be adjusted either by sliding the tube to increase and decrease its length or by opening and closing holes located along the tube in order to control where the air enters and exits the tube. Brass instruments involve the blowing of air into a mouthpiece. The vibrations of the lips against the mouthpiece produce a range of frequencies. One of the frequencies in the range of frequencies matches one of the natural frequencies of the air column inside of the brass instrument. This forces the air inside of the column into resonance vibrations. The result of resonance is always a big vibration - that is, a loud sound.

Woodwind instruments operate in a similar manner. Only, the source of vibrations is not the lips of the musician against a mouthpiece, but rather the vibration of a reed or wooden strip.The operation of a woodwind instrument is often modeled in a Physics class using a plastic straw. The ends of the straw are cut with a scissors, forming a taperedreed. When air is blown through the reed, the reed vibrates producing turbulence with a range of vibrational frequencies. When the frequency of vibration of the reed matches the frequency of vibration of the air column in the straw, resonance occurs. And once more, the result of resonance is a big vibration - the reed and air column sound out together to produce a loud sound. As if this weren't silly enough, the length of the straw is typically shortened by cutting small pieces off its opposite end. As the straw (and the air column that it contained) is shortened, the wavelength decreases and the frequency was increases. Higher and higher pitches are observed as the straw is shortened. Woodwind instruments produce their sounds in a manner similar to the straw demonstration. A vibrating reed forces an air column to vibrate at one of its natural frequencies. Only for wind instruments, the length of the air column is controlled by opening and closing holes within the metal tube (since the tubes are a little difficult to cut and a too expensive to replace every time they are cut).

Resonance is the cause of sound production in musical instruments. In the remainder of Lesson 5, the mathematics of standing waves will be applied to understanding how resonating strings and air columns produce their specific frequencies.

Edited January 4, 2016 by TonyAllTerrain

[skylineflyer]

Here are my results. I've been fighting for a year now and I've still gotten no where. This last time I finally got a pico test done, but I can't decipher it. If anything my vibration is now worse after they repositioned my cab.

[pm26]

So basically GM has learned the hard way that they cannot build an S class Mercedes with Yugo parts, and Yugo level assembly quality control .

Edited January 4, 2016 by pm26

[Wrench589]

Here are my results. I've been fighting for a year now and I've still gotten no where. This last time I finally got a pico test done, but I can't decipher it. If anything my vibration is now worse after they repositioned my cab.

What you are seeing is the vibration levels at various frequencies, expressed in unit of acceleration, "g"s in this case. 1 g is the equivalent acceleration caused by gravity. (9.81 m/s/s). In the vibration field, acceleration is quite often used to express vibration levels, especially for structure borne systems. Now, the Picoscope is a pretty cool vibration analyzer, because it also connects to the vehicles OBD port and thus can obtain realtime readings of engine speed and road speed. It also allows the manual setting of the tire size and axle ratio. With all that info, it can look at frequencies of particular interest when diagnosing vehicle vibrations, such as 1 times tire speed (T1), 2x tire speed (T2), and 3x tire speed (T3). Also, 1, 2 and 4x engine speed (e1, 2 and 3) and 1x and 2x props haft speed (P1 and p2).

 

Units of mg are actually milli-g's. An gm is a very low vibration level. In industrial machinery, which I work with for a living, we would not even both to report anything in mg's. Typical acceptance levels are in the 0.5 to 1.0 g level, for example. But, the human can feel vibration at very low levels so hence we are dealing in mg's.

 

If I look at your results, they really didn't improve much. T1 dropped by about 30%, T3 made a major drop to less than an mg, so that is significant. E1 also made a major drop to less than 1 mg (970 ug is a micro-g, which is 1/1000 of a mg), and E2 a fairly big drop. But p1 went up. And for the most part, the lower frequency vibrations will be associated with larger displacement vibrations, so I would expect the end result to be that the vehicle might feel kinda better, but still not good. And a long way for great.

 

Speaking of great, it would be great to get the same reading from a pickup that does not have any vibration issues. And, another totally different vehicle that rides perfectly smooth.

 

Last comment....the report did not state where the vibration readings were sensed. That can make a huge difference in the results. Would need that to do any comparison between this vehicle and another, or even this vehicle at different times.

 

All in all, thanks for sharing the data. Good info!

[Bayou_Vista]

Below is a link to Autoblog (Chris Bruce was the author) who wrote the story about GM SUV problems that was reported by Fox News. I sent a link to this thread in hopes they will update to their original story and talk about GM's truck problems as well. I'm posting this in case anyone wants to request their help.

 

http://www.autoblog.com/contact/tips/#01

[pm26]

Can we conclude that given the stiff frames and body mounts that GM has designed for these trucks for good handling, one must specify tighter tolerances and precision balancing on many rotating parts in order to keep vibrations to an acceptable level? And this includes high quality hubs, brake rotors, wheel, and tires.

[oneandzero]

Can we conclude that given the stiff frames and body mounts that GM has designed for these trucks for good handling, one must specify tighter tolerances and precision balancing on many rotating parts in order to keep vibrations to an acceptable level? And this includes high quality hubs, brake rotors, wheel, and tires.

From what I'm told GM has specified higher tolerances at least for the tires. In my case the dealer is saying my trucks vibration is due to the tires. A road force balance showed my tires needed 30lbs force to fix but apparently the tighter spec for our truck is around 20lbs. The result is my truck still vibrates supposedly due to this. I'm at the well you say it vibrates due to tires so I want them replaced and they say won't replace because tires are within the tire manufacturers spec.