2015 Silverado LT Vibration/Shaking

[Robby Smith]

that is strange, but shouldn't affect the vibration in the seat, console, floor, pedals etc.

My truck ONLY vibrates at the steering wheel. Today's test drive continued to stop vibrating when pushing hard & forward on steering wheel. When I reached speeds of 65-75, there was little to no vibration. (at least nothing to be concerned about)

[Jesse Davidson]

My truck ONLY vibrates at the steering wheel. Today's test drive continued to stop vibrating when pushing hard & forward on steering wheel. When I reached speeds of 65-75, there was little to no vibration. (at least nothing to be concerned about)

Thats lucky, but don't be surprised if it gets worse, especially if they try to fix it.

[14silverado4.3]

Update,

 

I received a call from the dealership (thought they forgot about me) that GM has been working on a solution for the 4-cylinder vibration issue. Dealer would like me to drop off the truck to apply the fix. Not sure what their fix is but I'll find out. I’ll be dropping the truck off at the dealership on 10/13/15, will update when I get it back.

 

Thanks,

 

MA

MA - ANY UPDATE ON THIS?

[Jesse Davidson]

missed that, whoops.

 

I don't see how they can fix it without disengaging the Deactivation all together

[Potts]

Man I need to stay away from these threads unless I Start having a problem. I am so in love with my truck, I would be completely mortified if this started happening. It really scares me that it seems to crop up for some people too. At first I thought this issue sounded like most people had it from the get go and that since I didn't I was lucky/out of the woods, but I'm seeing more and more of the posts where people were vibration free and then it started. I've got about 900 miles on mine and so far so good (knocking on wood). I have my second baby coming in January and am so busy with life and work I would be losing my fricking mind if I were dealing with this. I feel so bad for you folks, I really do. I truly hope they figure out a way to cure this. They are such beautiful trucks otherwise. I can't even imagine what this will do to resale values for these model years as well. This really is criminal at this point.

 

I would be so pissed if they kept tearing apart my brand new truck trying different crap too. No one should have their brand new truck screwed with this much. Who knows what other issues they are causing every time they tinker with it.

 

Seriously, best of luck to all you poor souls...I feel for you, I truly do.

 

 

Sent from my iPhone using Tapatalk

[Potts]

Also, I really want to know what the one dude was talking about where he said the lawyer said they know what the issue is but it would be too expensive to fix. Someone should start a matrix to track all the different confirmed build dates, model years, models, and configurations that have the vibration issue so we can look for a pattern in build, model, configuration. It sounds like pretty much every model/config can be affected but it would be nice to see laid out.

 

I'd be happy to put a spreadsheet together that could track this if someone can help with getting people to populate it. Once i have some data I could run some reports to break it down and see if there is an area where the problem appears to be more prevalent. Let me know if anyone wants to work on that.

 

 

Sent from my iPhone using Tapatalk

[Jesse Davidson]

Also, I really want to know what the one dude was talking about where he said the lawyer said they know what the issue is but it would be too expensive to fix. Someone should start a matrix to track all the different confirmed build dates, model years, models, and configurations that have the vibration issue so we can look for a pattern in build, model, configuration. It sounds like pretty much every model/config can be affected but it would be nice to see laid out.

 

I'd be happy to put a spreadsheet together that could track this if someone can help with getting people to populate it. Once i have some data I could run some reports to break it down and see if there is an area where the problem appears to be more prevalent. Let me know if anyone wants to work on that.

 

 

Sent from my iPhone using Tapatalk

Yes, I had lawyers looking into this. They had their industry experts and insiders come back with the mounts on the trucks ie: engine, body frame etc. the firm said until the trucks are out of warranty there is nothing they can do because their firm doesn't handle lemon law type cases. Which as long as the trucks are in warranty, is what this would be. Because that info was from "confidential sources" I couldn't say it, but once someone else came in saying that their dealer said it is the mounts, and that GM wasn't going to do anything about it, I could legally chime in to confirm that.

 

A couple days ago I shot an email to a few of my old engineering professors, one of which was a consultant to toyota for the structural integrity of their roofs, to see if he still has any industry contacts that may be able to give me some more info. I'm waiting to see what he says.

 

GM knows and has known what the problem is for quite a while, they are not going to fix it. I will be filing with the BBB or suing GM at the end of the month as I have my 3 repair attempts (depends on how they want to act toward a full buy back... they want to play hard ball, I will play hard ball)

 

Only reason I am keeping it that long is I am currently getting paid to use my truck for work, that will end in Mid December so I figure that will be about the time the case will be settled and I get a brand new truck after getting paid to use this one for 4 months lol... gotta think ahead hahaha

[raven3]

Have taken a keen interest to the vibration issue topic, since spent my 40+ year career in the field of applied mechanics dynamics and vibration.

Read lots of replies and inputs, because planning on purchasing a new light duty truck.

 

The light duty PU truck is designed to carry a nominal 2000# load in the box.

Leaf spring and coil spring suspension and frame are also designed to handle this load traveling on rough road conditions.

The steel frame is now lighter and more rigid than the open channel frames of past truck generations.

Leaf springs have not changed much since previous generations were still rated at nominal 1/2 capacity.

The cabin structure is now lighter weight to improve MPG ratings.

 

Dynamic energy stem from several sources to produce vibration in structures and sub structures.

The cabin box is a structure. The cabin roof and floor are substructures.

1. Wheels are a random source of dynamic energy from road pertibations.

2. Drive shaft is a source of sinusoidal dynamic vibration energy.

3. Engine is a source of sinusoidal dynamic vibration energy.

4. Torque converter is a source of sinusoidal dynamic vibration energy.

 

The trucks are mass produced. There is a wide manufacturing tolerance on parts and assemblies.

The engine pistons are pulled from bin. All the pistons are not of equal weight.

In a performance engine all pistons are machined to have equal weight.

It is common knowledge that a V8 engine runs smoother and with less vibration than a V6 engine.

It is the luck of the draw. Some engines come off the assembly more balanced than others.

Some are in left field and some are in right field depending on what side of the bell curve the stack up tolerances add. Very few engines are at the center of the bell curve that are perfectly balanced.

 

Same thing goes for the drive shaft, torque converter , tires & wheels.

The vibration energy from the major sources are all transmitted to the frame.

The elastomer body mounts help isolate some of the vibration energy from the frame to the cabin structure.

 

The lighter weight cabin structure is more sensitive to vibration than the more heavy weight cabins of previous generations.

The cabin floor will vibrate more. The cabin will vibrate more.

The vibrating steering column is supported from the cabin structure.

Decreasing the durometer hardness of the rubber cabin vibration isolators and increasing the thickness of vibration isolators would decrease the vibration energy transmitted to the cabin structure.

In the past aluminum drive shafts were used to decrease the vibration energy generated by drive shafts.

Some drive shaft assemblies are balanced better than others.

It is all important to have the pinion shaft parallel to transmission output shaft in the operating condition.

Typically, the pinion shaft is set 1 to 2 degrees lower than the transmission shaft to allow for rotation of the rear axle from applied drive line torque.

Incorporating an oil filled engine mount to the steel frame would decrease the engine vibration energy transmitted to the frame.

Tire cupping can be a major source of vibration caused where the weight distribution between the front wheels and rear wheels is not equal and rough concrete road surfaces.

The rear leaf springs and shocks absorb energy in the form of strain energy for springs and heat for the shocks.

A characteristic of the truck is stiff suspension. So much of the energy generated where the tire impacts the road will be transmitted to the frame.

 

My take on the vibration issue is GM should use more compliant elastomer body mounts and more compliant engine mounts to compensate for the lighter weight cabin.

[Jesse Davidson]

Have taken a keen interest to the vibration issue topic, since spent my 40+ year career in the field of applied mechanics dynamics and vibration.

Read lots of replies and inputs, because planning on purchasing a new light duty truck.

 

The light duty PU truck is designed to carry a nominal 2000# load in the box.

Leaf spring and coil spring suspension and frame are also designed to handle this load traveling on rough road conditions.

The steel frame is now lighter and more rigid than the open channel frames of past truck generations.

Leaf springs have not changed much since previous generations were still rated at nominal 1/2 capacity.

The cabin structure is now lighter weight to improve MPG ratings.

 

Dynamic energy stem from several sources to produce vibration in structures and sub structures.

The cabin box is a structure. The cabin roof and floor are substructures.

1. Wheels are a random source of dynamic energy from road pertibations.

2. Drive shaft is a source of sinusoidal dynamic vibration energy.

3. Engine is a source of sinusoidal dynamic vibration energy.

4. Torque converter is a source of sinusoidal dynamic vibration energy.

 

The trucks are mass produced. There is a wide manufacturing tolerance on parts and assemblies.

The engine pistons are pulled from bin. All the pistons are not of equal weight.

In a performance engine all pistons are machined to have equal weight.

It is common knowledge that a V8 engine runs smoother and with less vibration than a V6 engine.

It is the luck of the draw. Some engines come off the assembly more balanced than others.

Some are in left field and some are in right field depending on what side of the bell curve the stack up tolerances add. Very few engines are at the center of the bell curve that are perfectly balanced.

 

Same thing goes for the drive shaft, torque converter , tires & wheels.

The vibration energy from the major sources are all transmitted to the frame.

The elastomer body mounts help isolate some of the vibration energy from the frame to the cabin structure.

 

The lighter weight cabin structure is more sensitive to vibration than the more heavy weight cabins of previous generations.

The cabin floor will vibrate more. The cabin will vibrate more.

The vibrating steering column is supported from the cabin structure.

Decreasing the durometer hardness of the rubber cabin vibration isolators and increasing the thickness of vibration isolators would decrease the vibration energy transmitted to the cabin structure.

In the past aluminum drive shafts were used to decrease the vibration energy generated by drive shafts.

Some drive shaft assemblies are balanced better than others.

It is all important to have the pinion shaft parallel to transmission output shaft in the operating condition.

Typically, the pinion shaft is set 1 to 2 degrees lower than the transmission shaft to allow for rotation of the rear axle from applied drive line torque.

Incorporating an oil filled engine mount to the steel frame would decrease the engine vibration energy transmitted to the frame.

Tire cupping can be a major source of vibration caused where the weight distribution between the front wheels and rear wheels is not equal and rough concrete road surfaces.

The rear leaf springs and shocks absorb energy in the form of strain energy for springs and heat for the shocks.

A characteristic of the truck is stiff suspension. So much of the energy generated where the tire impacts the road will be transmitted to the frame.

 

My take on the vibration issue is GM should use more compliant elastomer body mounts and more compliant engine mounts to compensate for the lighter weight cabin.

Very well written, I am a Mechanical Engineer and went into a similar analysis about how the vibrations will end up detrimental to the vehicle on roughly page 350 or so in another vibration thread. I do agree with you, and can confirm the mounts as the issue.

[tnchevy]

I am not an engineer by any means but I think you are heavily exaggerating saying it will be "detrimental" to the vehicle. In my line of work I am offroad on daily basis, more than 99% of the public who own 4x4 trucks. We beat the crap out of them, dent drive shafts, ride around with out of balance tires, warped rotors, etc. None of my work trucks ever stay vibration free for more than a few months but we ride them till about 150k miles or so (3 to 4 years) and then buy new and auction the old ones off. They look like crap when we get rid of them but the engine runs, tranny shifts, and front and rear diffs are still functioning. Unless the vibration is coming from diffs that are all screwed up, those of you with the vibrating trucks will be riding them with little to no problems till you decide to get rid of them. My truck also still vibrates but it comes and goes based on how long it has been sitting, temps, tire pressure, etc.

Edited October 10, 2015 by tnchevy

[raven3]

Light duty truck OEMs brag about the hydro formed high strength street frames.

High strength steel has greater yield strength than mild or even low strength steel, which

means the material can be loaded with greater stress levels before yielding the material to cause permanent

deformation.

Though the frames have be optimized for minimum weight, the fully boxed section results in a stiffer frame.

A stiffer frame will flex less that previous generations with open section frame rails in both bending and torsion

modes. Since the high strength frame has less flex, then less road generated vibration energy is absorbed by the frame in the form of strain energy, compared to a more compliant mild steel frame with open section side rails and cross members.

The non absorbed road generated vibration is then transmitted to the cabin structure through the elastomer body mounts. More compliant body mounts would absorb a percentage of the energy in the form of heat.

Just finished a project of replacing flattened out rubber body mounts on a vintage light truck with urethane mounts.

The process is quite time consuming. Doubt if GM would replace the cabin body mounts to reduce the amount of vibration felt in the cabin. Semi truck tractors with steel leaf spring suspension transmit a large amount of vibration energy to the cabin structure. Knew a long haul truck driver that had to take pain medication for neck pain resulting from years of cabin low frequency vibration.

 

Understand why an individual who purchases a so called "luxury" light duty truck has the expectation of a comfortable ride quality.

When this ride quality is compromised from excessive cabin vibration, the complaints are launched.

 

One source of vibration that can be reduced would be to replace the steel drive shaft with an aluminum drive shaft. The tube between the two U-Joints accelerates and deaccelebrates twice with each rotation, even if the drive shaft is perfectly aligned, balanced & phased.

Acceleration creates a force. This force is transmitted to the frame from the drive shaft tube through the rear axle to the leaf springs and to the frame. The drive shaft vibration energy is also transmitted through the transmission or transfer case to the transmission mount and then the cross member to the frame rails.

An alumnium material drive shaft will reduce the amount of generated vibration enuergy.

This assembly is not horribly expensive, but being aluminum would be more sensitive to fatigue cracking than a steel drive shaft. GM may have considered this trade off with the 100K mile power train warranty.

If had an issue with excessive vibration this custom modication would be first on the list.

The labor to replace the drive shaft is minimal.

 

Noticed some folks solved their excessive vibration issue with "Just Tires".

Could purchase an aluminum drive shaft for much < $ than a set of LT tires.

[tnchevy]

If I am not mistaken the majority of the silverado/sierras have a hollow aluminum drive shaft anyway.

[raven3]

What happened to 15" steel rims?

17", 18", 20" rims use lower profile tires with more rigid side walls.

Always thought the purpose of rubber tires was to absorb the impact energy from the road deformation.

Lower profile tires deform less than higher profile tires.

 

It appears the crew cab configuration, assembled in Mexico incorporates the large 5" diameter aluminum material drive shaft, while the double cab configuration assembled in Fort Wayne, IN ,incorporates a smaller diameter steel material drive shaft.

Edited October 11, 2015 by raven3

[tnchevy]

The smallest rim you can have on these model trucks is 17" because the brake rotors are much larger than on older model trucks. You are mistaken on your drives haft assumption. Mine is a double cab built in IN and it has the aluminum drive shaft. My 2002 model also had an aluminum drive shaft.

[raven3]

Acknowledge that your double cab has an aluminum material drive shaft.

Maybe the V8 have aluminum, while the V6 has steel drive shaft.

Ran across a 14 double cab recently that had a steel drive shaft shaft made in Canada.

 

Believe first year for 17" rims is 2008 and first year for 16" rims is 1999 when Chevrolet PU truck was renamed Silverado.

Prior to 1999, 15" rims where used.

 

Some research indicates

15" rims used 235/75/15 tires with 28.9" OD resulting in 7.0" wall height.

16" rims used 235/75/16 tires with 29.8" OD resulting in 6.9" wall height

17" rims uses 245/70/17 tires with 30.6" OD resulting in 6.8" wall height

The 15" rim tire has slightly higher wall than current 17" rim tire, resulting in slightly more compliant ride.

Edited October 11, 2015 by raven3