Shake or Vibration Issues

[14silverado4.3]

Vibration is a driveshaft problem that can either transverse or torsional.

Transverse vibration is the result of unbalance acting on the supporting shafts as the driveshaft rotates. When a part having an out-of-balance, or heavy side, is rotated an unbalanced force is created that increases with the square of the speed. The faster the shaft turns, the greater the unbalance force acting on the shaft.

The force produced by this out of balance condition tends to bend the supporting members. As the supporting members have a natural frequency of vibration similar to a swinging pendulum, a violent vibration may exist at certain periods when the speed of rotation and the natural frequency of supports coincide.

Each end of the shaft must be balanced individually as each support is responsive to an out of balance condition in portion of the shaft it supports. Out-of-balance affects operating conditions only when rotating.

Transverse vibration caused by a driveshaft out-of balance will usually emit sound waves that you can hear and mechanical shaking that you can feel. The force from out-of-balance increases with speed, not torque load. The driveshaft speed is determined by vehicle speed and the vibration is demonstrated best by road testing the vehicle to operating speed, disengaging engine, and checking vibration while coasting with engine noise eliminated.

Torsional vibration, although similar in effect to transverse vibration, is an entirely different motion. The transverse vibration is a bending movement where as torsional vibration is a twisting motion.

The energy to produce to torsional vibration can occur from the power impulses of the engine or from improper u-joint angles. This type of vibration is difficult to identify in road testing but certain characteristics do exist. It causes a noticeable sound disturbance and can occasionally transmit mechanical shaking.

Torsional vibrations can exist at one or more periods any place in the operating range and tend to be more severe at lower speeds. Changes in torque load (part-to-full throttle) usually affect the vibration. The non uniform velocity obtained when a u-joint operates at an angle produces torsional vibration. In a driveline having two or more joints in series, it is desirable to have the individual joint angles arranged such that the net result minimizes non uniform velocity characteristics over the system.

It is practically impossible to maintain the desired joint angles throughout the operating range. Therefore, it is necessary to determine some maximum limit of torsional excitation which can be considered as generally acceptable.

The amount of torsional excitation which can be accepted without causing excessive disturbance depends upon operating speed and characteristics of supporting structures and other units in the driveline and drivetrain system.

Other vibrational problems in a driveshaft could be caused by worn or damaged u-joints. These joints must be constantly maintained according to manufacture's lubrication specifications.

[14silverado4.3]

http://www.machineservice.com/technical-101/vibrational-issues/

[07SLT]

Are the vibration issues with these trucks something you notice on day one of purchase or something that comes on gradually with age?

[Jesse Davidson]

Are the vibration issues with these trucks something you notice on day one of purchase or something that comes on gradually with age?

it varies, some have noticed it when they buy it, and are told "the tires have flat spots from sitting on the lot, it needs 500 miles to round back out" or something along those lines. others like myself noticed it after a little time, mine was about 250 miles, but ive seen some people here not get it until 13000 miles

Vibration is a driveshaft problem that can either transverse or torsional.

Transverse vibration is the result of unbalance acting on the supporting shafts as the driveshaft rotates. When a part having an out-of-balance, or heavy side, is rotated an unbalanced force is created that increases with the square of the speed. The faster the shaft turns, the greater the unbalance force acting on the shaft.

The force produced by this out of balance condition tends to bend the supporting members. As the supporting members have a natural frequency of vibration similar to a swinging pendulum, a violent vibration may exist at certain periods when the speed of rotation and the natural frequency of supports coincide.

Each end of the shaft must be balanced individually as each support is responsive to an out of balance condition in portion of the shaft it supports. Out-of-balance affects operating conditions only when rotating.

Transverse vibration caused by a driveshaft out-of balance will usually emit sound waves that you can hear and mechanical shaking that you can feel. The force from out-of-balance increases with speed, not torque load. The driveshaft speed is determined by vehicle speed and the vibration is demonstrated best by road testing the vehicle to operating speed, disengaging engine, and checking vibration while coasting with engine noise eliminated.

Torsional vibration, although similar in effect to transverse vibration, is an entirely different motion. The transverse vibration is a bending movement where as torsional vibration is a twisting motion.

The energy to produce to torsional vibration can occur from the power impulses of the engine or from improper u-joint angles. This type of vibration is difficult to identify in road testing but certain characteristics do exist. It causes a noticeable sound disturbance and can occasionally transmit mechanical shaking.

Torsional vibrations can exist at one or more periods any place in the operating range and tend to be more severe at lower speeds. Changes in torque load (part-to-full throttle) usually affect the vibration. The non uniform velocity obtained when a u-joint operates at an angle produces torsional vibration. In a driveline having two or more joints in series, it is desirable to have the individual joint angles arranged such that the net result minimizes non uniform velocity characteristics over the system.

It is practically impossible to maintain the desired joint angles throughout the operating range. Therefore, it is necessary to determine some maximum limit of torsional excitation which can be considered as generally acceptable.

The amount of torsional excitation which can be accepted without causing excessive disturbance depends upon operating speed and characteristics of supporting structures and other units in the driveline and drivetrain system.

Other vibrational problems in a driveshaft could be caused by worn or damaged u-joints. These joints must be constantly maintained according to manufacture's lubrication specifications.

what are you trying to say with this?

[14silverado4.3]

it varies, some have noticed it when they buy it, and are told "the tires have flat spots from sitting on the lot, it needs 500 miles to round back out" or something along those lines. others like myself noticed it after a little time, mine was about 250 miles, but ive seen some people here not get it until 13000 miles

 

what are you trying to say with this?

I am not sure, as a follow up. Try cracking the windows on the highway and tell me what you all feel? Is there a change in the amplitude or felt vibration.

[KingstonMom1976]

Had my rear shocks changed yesterday as they had failed. Truck has 30,000 kms on it. Went home...Vibration was twice as bad. Truck is going in Monday and Service Manager said they are keeping it until its fixed. Getting me a rental and going at it. This is the second time they have kept it...I came armed with the bulletin re: picoscope, Driveshaft, etc....they are doing the full meal deal. I don't blame my dealership. GM Should be ashamed of themselves. Nobody, let alone a woman, should have to deal with mechanical BS like this. So happy I hung out in my grampies garage for years. I at least have some knowledge...pity the poor sap who does not.

Edited May 13, 2016 by KingstonMom1976

[Fountain_NGA]

So I've had my 2016 Silverado replacement for about a month and a half and what's weird if the vibration is kinda there. I will notice it as soon as I hit 73mph, but even keeping vehicle at that speed, it disappears within 10 seconds of starting (I mean completely disappears). My 2015 Silverado would keep on shaking at that speed until I dropped below 70mph. Don't know if that is just a sign of things to come, of if they've found a way to dampen it after it starts now. I do know my truck was built towards the end of February of this year, so there may have been an engineering change to help with the issue.

[abominable z71]

Well I would like to retract my statement that the vibration is not likely to cause hardware to loosen up and create a safety concern. Yesterday on my way home from work I had a message pop up to let me know traction control had been disabled. I was like WTF, about 30 seconds later another message popped up telling me my brake fluid was low and needed attention, no I'm like really WTF. Pulled over and popped the hood sure enough the brake fluid was below the min mark. Had to go somewhere, did the 360 walk around and discovered my right rear wheel was covered in brake fluid. First thought bad wheel cylinder, fortunately there was a Napa auto parts 400 yards up the road. I asked a guy coming out of the store if he could push the brakes for me while I inspected things. He obliged and I fluid came gushing out of the connection point where the brake line attached to the caliper, grabbed the bolt with my fingers and could not turn it. Fortunately he was in his work truck and had some tools. Put a box end wrench on it and discovered it was extremely loose. The truck is 1 year old with 20k miles and the brakes have never been touched, tightened the bolt up and the leak went away. Anyone that wrenches on cars knows that brake fluid destroys most finishes needless to say it ruined the PVD chrome on my wheel and the paint on the inside of the wheel not to mention the time spent bleeding the brakes and trying to clean the fluid off the the painted parts (springs, axle housing, dust shield, etc.) I'll be going underneath with a can of Krylon to do some touch up painting.

 

In the end why was it loose? Improper torque from the factory? or did it vibrate loose from the constant 70+ mph vibe, my daily commute is 15 miles each way 75 mph. My opinion it vibrated loose and it points to the fact the my vibration is probably coming from the right rear of the truck, but that and 50 cents will make a phone call if you can still find a pay phone. The other 3 lines were nice and tight, could have been improper torque from the factory.

[steelcity]

Well I would like to retract my statement that the vibration is not likely to cause hardware to loosen up and create a safety concern. Yesterday on my way home from work I had a message pop up to let me know traction control had been disabled. I was like WTF, about 30 seconds later another message popped up telling me my brake fluid was low and needed attention, no I'm like really WTF. Pulled over and popped the hood sure enough the brake fluid was below the min mark. Had to go somewhere, did the 360 walk around and discovered my right rear wheel was covered in brake fluid. First thought bad wheel cylinder, fortunately there was a Napa auto parts 400 yards up the road. I asked a guy coming out of the store if he could push the brakes for me while I inspected things. He obliged and I fluid came gushing out of the connection point where the brake line attached to the caliper, grabbed the bolt with my fingers and could not turn it. Fortunately he was in his work truck and had some tools. Put a box end wrench on it and discovered it was extremely loose. The truck is 1 year old with 20k miles and the brakes have never been touched, tightened the bolt up and the leak went away. Anyone that wrenches on cars knows that brake fluid destroys most finishes needless to say it ruined the PVD chrome on my wheel and the paint on the inside of the wheel not to mention the time spent bleeding the brakes and trying to clean the fluid off the the painted parts (springs, axle housing, dust shield, etc.) I'll be going underneath with a can of Krylon to do some touch up painting.

 

In the end why was it loose? Improper torque from the factory? or did it vibrate loose from the constant 70+ mph vibe, my daily commute is 15 miles each way 75 mph. My opinion it vibrated loose and it points to the fact the my vibration is probably coming from the right rear of the truck, but that and 50 cents will make a phone call if you can still find a pay phone. The other 3 lines were nice and tight, could have been improper torque from the factory.

Or is one of your neighbors trying to get rid of you, lol!

[abominable z71]

Or is one of your neighbors trying to get rid of you, lol!

LoL, Girlfriends ex husband maybe.

[Alter Ego Trip]

So I've had my 2016 Silverado replacement for about a month and a half and what's weird if the vibration is kinda there. I will notice it as soon as I hit 73mph, but even keeping vehicle at that speed, it disappears within 10 seconds of starting (I mean completely disappears). My 2015 Silverado would keep on shaking at that speed until I dropped below 70mph. Don't know if that is just a sign of things to come, of if they've found a way to dampen it after it starts now. I do know my truck was built towards the end of February of this year, so there may have been an engineering change to help with the issue.

 

I'm pretty sure Chevrolet had located the cause for the vibration. I have yet to detect vibration on any of our current trucks on my lot. I think they kept this a hush hush to avoid admitting fault on the 14-15 models.

 

After 9 months or arguing (and the vibration consistently getting worse on my truck) GM finally has agreed to move forward with a buyback. Funny part is; they are trying to get me to pay .25 per mile for depreciation, lol. I initially called in with the complaint back at 300 miles. It took them 7,000 miles to finally agree to do something about it. Not my problem they drug their feet.

 

I truly believe that this problem will never be resolved. I think it's a design flaw that is embedded into the architecture of the vehicle and cannot be remedied. Mine was certainly worse than a lot of others I have encountered. My truck actually shook at around 45 miles per hour (very severe) and turned into a vibration/droning till about 80. Impossible to drive the truck at any speed without dealing with the problem.

Edited May 13, 2016 by Alter Ego Trip

[Jesse Davidson]

I have given up on trying to find an attorney, nobody wants to touch it since there is no physical injury that can be directly attributed to this. I am sending a final repair notice on Monday and will see where it goes.

[Jesse Davidson]

I am not sure, as a follow up. Try cracking the windows on the highway and tell me what you all feel? Is there a change in the amplitude or felt vibration.

I typically don't drive on the highway with the windows down because I don't like the wind noise, but there is a weird pressurization type of thing with them down., maybe a little worse than other cars in my opinion, but I can't say for sure. never noticed any change in vibration from it.

Edited May 14, 2016 by Jesse D

[FL335i]

The red flag for me was when the dealer parts counter told me GM doesn't make shims for the rear axle.... I'd have to buy them aftermarket. That in itself pretty much tells you why they vibrate. Mass produced cars and you know the angles are not perfect on all of them. I'm doing a 45k service today. LOF, Tire rotation, brake fluid flush, Tcase fluid etc and I will bust out the angle finder and spend more time on this today.

Edited May 14, 2016 by FL335i

[Snoringbear]

I typically don't drive on the highway with the windows down because I don't like the wind noise, but there is a weird pressurization type of thing with them down., maybe a little worse than other cars in my opinion, but I can't say for sure. never noticed any change in vibration from it.

Virtually all modern cars/pickups will create harmonic buffering when driving with the a window down. I've read that the reason is because these vehicles are designed aerodynamically to be driven at speed with windows up. Older vehicles, say before ac was so common weren't designed for maximizing aerodynamics. They were designed to achieve a certain look or style. Anyway, I do like to drive with my window down on occasion because I look so cool when doing "one arm driving", hahal! The way I minimize buffing is to crack the right-rear window about two or three inches. This little trick seems to work for me