Shake or Vibration Issues

[oneandzero]

Another thing that bothers me is another problem my trucks having and I can't help think the two are related. It's the way the transmission shifts, way to soon, doesn't down shift etc etc. and all in the name of supposed fuel economy. Anyway what I'm noticing is when the truck is going 55 kph doing only 1000 RPM there's a lot of vibration also. I'm thinking in this instance the source is the engine laboring due to the high gear its trying drive. I now drive in tow haul mode because its the only way I can stand the truck while driving in the city. I forgot yesterday to switch out of tow haul mode while on the highway driving 80 kph and noticed it drove somewhat smoother. Maybe the whole drive line needs some kind of tune, maybe its a harmonic type of thing. The dealer is supposed to reset the transmission back to factory defaults so lets see what happens after that. Don't think this motor deals well with low RPM and that's got me wondering if changing the rear end from 3.42 to 3.73 may help. I'm not seeing the so called good fuel mileage anyway.... especially in my case when the engine always seems to be laboring.

Edited December 25, 2015 by oneandzero

[pm26]

merry Christmas to you as well

 

Has anyone with shakes lifted the rear wheels off the ground and run the vehicle to see if rear wheels/rear end/ driveshaft shake?

 

It's strange because it's perfectly smooth at speeds below 20. Like parking lots and such.

There is a reason why wheels are not balanced on tractors, loaders, and all kinds of slow moving vehicles. Vibration will be minimal at low speeds below 20 MPH even with unbalanced wheels.

[rshad]

I have had my truck up to almost 80MPH and then put the truck into Neutral, As the truck starts to slow to around 74 it vibrates again. The engine RPM's are around 600 just like at idol when you still feel the vibration so would this rule out the trans and engine?

[allend55]

purchased 2015 hi country.....$.62,000.....very bad shake from east side dealer....dropped at Cadillac dlr before I got home....had 3 days....said two tire changes,,,cant fix bent frame,,,60 mi on trk.back to selling dle,box offset 1 in.redrilled straight,still shake,,,,,new tires,still shake,,,wanted 11,000 to trade for like trk...trk never in garage always at dlr.bad frame,,,big joke,to them,,,bad service at freeway chev,,,,,,,,sales laughed said tough we don't build

[allend55]

big problems at gm with shake vibrations.............many buybacks,lawsuits................several dlrs fighting and suing........no fix....expect customer to live with it........

[jpcons]

I am a GM employee and having the same problem with my truck. I have been in touch with district manager and spoke to the engineers directly and no cure has been found. The problem is the new designed frame multiplies the vibration and shakes the truck. The picoscobe puts hose clamps on he drive shaft in a attempt to calm the vibration with no luck.

Gm offered a buy back but they have nothing to offer that fits my needs and don't want to trade to another vibrator. I have a 2015 work truck regular cab short bed plow and tow package that I can not drive over 70mph year long and with the plow on you can not drive over 40mph ( a complete other problem gm has with out a cure)

[mjb4450]

( a complete other problem gm has with out a cure)

 

 

No surprise there. Mine had a mild, intermittent but livable vibration but had a few other problems that also were not able to be corrected. It seems GM has all kinds of defects that they either cannot or will not fix. That is why mine is gone.

[Jed Blanks]

I am a GM employee and having the same problem with my truck. .... The picoscobe puts hose clamps on he drive shaft in a attempt to calm the vibration with no luck.

hose clamps on driveshaft?

Just in random spots or how do you decide where/what orientation?

Edited December 26, 2015 by jblanks

[dave07]

My truck had been sitting for a few days since we have been using my wife's Lexus for Christmas traveling. We are in Pittsburgh and I wanted to check out the field and stream store. I got on the highway which is about a mile from my mother in laws house. Traffic around here goes 80 mph everywhere . I got my truck up to 80 mph and it was shaking very badly. On the way back I took it back up to 80 and it was smooth as glass.

 

I'm wondering if my tires had some flat spots from sitting for couple of days which in turn caused the vibration.

 

 

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[Wrench589]

My truck had been sitting for a few days since we have been using my wife's Lexus for Christmas traveling. We are in Pittsburgh and I wanted to check out the field and stream store. I got on the highway which is about a mile from my mother in laws house. Traffic around here goes 80 mph everywhere . I got my truck up to 80 mph and it was shaking very badly. On the way back I took it back up to 80 and it was smooth as glass.

I'm wondering if my tires had some flat spots from sitting for couple of days which in turn caused the vibration.

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Very likely it had flat spots. In fact, GM is pretty adamant that the dealers drive the vehicle at least 15 miles before doing any Roadforce Balancing to get rid of any flat spots. And, your experience would be consistent with that. What is not clear, is why these vehicles are so bloody sensitive to flat spots. I can leave any of my vehicles sit for weeks on end and when I drive away, zero vibration right from the get go. So why are these GM/Chevys so fricken sensitive. It seems like if the wheels and tires are not 100% perfect! get some kind of vibration (or buffeting, in the case of the SUVs). GM can blame the tires all they want, but there is. I other vehicle on the market today that is that sensitive, not even in the rest of the GM brand! So unless GM plans to design and manufacture the perfect tire for us, it appears these vehicles will always be a problem.

 

FYI, I've notice the buffeting on our Yukon is much worse the first 5 or 10 miles, then gets a little better. So, likely the flT spots on the tire making it worse. One of these days I'm going to jack up a wheel aft it's been sitting all night and measure how much of a flat spot is there. I bet it's very minimal.

[Wrench589]

The problem is the new designed frame multiplies the vibration and shakes the truck.

Do you have any more info on this? Is this what GM is saying the root cause is? This sound a lot like the "frame beaming" I read about on an older generation of GM trucks. There was a TSB on fixing it. Well, not he frame itself, but new cab mounts to reduce how much transmitted to the passengers. Sound like a very similar thing.

[abominable z71]

hose clamps on driveshaft?

Just in random spots or how do you decide where/what orientation?

This actually is a pretty common way to troubleshoot vibration from the driveline due to imbalanced mass. Measure about 6 inches from the rear pinion yoke and then using a sharpie divide the circumference of the tube into 4 equal parts 90 degrees apart and draw a small mark number them to keep track if it helps. Put your hose clamp around the drive line and tighten it up so the screw portion of the worm gear is centered on your first mark. Drive the truck and see how it feels, then rotate the location of the clamp to your next mark and see if things are better or worse when driving it. When you determine which mark feels the best you can then adjust in small 1/2" increments from there to dial it in. Add a second clamp right next to it after that to see if the extra weight improves things, you can then repeat the process for the front end of the shaft by the transmission/transfer case u joint but this is typically not necessary. Often times this is done using a strobe light and vibration analyzer like an EVA2. That eliminates the need to drive the truck between each adjustment of the clamp location. If you search youtube for EVA driveline balancing there's a good video from a college autoshop class that shows the whole procedure using an EVA2. Just do the same thing but drive the truck between each adjustment, your butt will tell you what to do from there.

[abominable z71]

Do you have any more info on this? Is this what GM is saying the root cause is? This sound a lot like the "frame beaming" I read about on an older generation of GM trucks. There was a TSB on fixing it. Well, not he frame itself, but new cab mounts to reduce how much transmitted to the passengers. Sound like a very similar thing.

GM needs to look at redesigning their body mounts or rebracing the frame to change the overall stiffness matrix or resonant frequency of the frame itself. I find it hard to believe they don't have access to software and computing power to run an FEA on it, they know what the vibration frequency and force vector is that is causing the damn thing to resonate. Maybe they should sub contract the job to Honda at least they are acknowledging and working on fixing the CRV vibrations. The worst part is they expect the consumer to accept it because they are too inept to fix it. Almost 3 years since they released this platform and who knows how many years in development before that at least 3. The first nuclear bomb was created in less time. Should have let them go bankrupt, this is the kind of crap that is the reason they were failing in the first place. I wonder what the executive bonuses looked like this year considering they have been selling the crap out of these trucks even though at serious reduction to MSRP, it just goes to show how over priced these trucks are in the first place because you know even at 10K off they're still making money. Sorry, that's then end of my diatribe.

[pm26]

GM needs to look at redesigning their body mounts or rebracing the frame to change the overall stiffness matrix or resonant frequency of the frame itself. I find it hard to believe they don't have access to software and computing power to run an FEA on it, they know what the vibration frequency and force vector is that is causing the damn thing to resonate. Maybe they should sub contract the job to Honda at least they are acknowledging and working on fixing the CRV vibrations. The worst part is they expect the consumer to accept it because they are too inept to fix it. Almost 3 years since they released this platform and who knows how many years in development before that at least 3. The first nuclear bomb was created in less time. Should have let them go bankrupt, this is the kind of crap that is the reason they were failing in the first place. I wonder what the executive bonuses looked like this year considering they have been selling the crap out of these trucks even though at serious reduction to MSRP, it just goes to show how over priced these trucks are in the first place because you know even at 10K off they're still making money. Sorry, that's then end of my diatribe.

But they do not appear to be inept at raising truck prices through the roof, cutting quality control, moving parts production and vehicle assembly to Mexico, making equipment that was previously standard optional at extra cost, and inventing new tricks how to rip off customers, for example by forcing them to buy levels of equipment they do not necessarily want or need just to get the 6.2 liter optional engine.

Edited December 26, 2015 by pm26

[C6Bill]

So what do you suggest? A 3000 mile test drive before you buy?

 

 

Wow, what a wonderful idea. Wish I had thought of that.

 

I was thinking that people should just stop buying them. But your idea sounds much better. With forward thinking like that you should apply for a job as an engineer at GM, they'd probably make you senior management.

 

 

But on that note, I'm out. You guys enjoy your vibrators.

 

 

PS Mods, feel free to close my account. I'd never buy another GM product.

Edited December 27, 2015 by C6Bill