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Posted

When people post can you please give us more info on the truck like make, model, type ( crew cab etc), 2wd or 4wd, rim size and brand of tire, month and year it was built. maybe we can narrow down which style is more of a issue or maybe it's just hit and miss on all styles

I tried this too but it seams to be all trucks 4wd or 2wd and happens equally in all the different style configurations

 

the thing that I was still fuzzy about after my efforts to find a common link in all this was the engines involved, never could narrow it down if it was just with the 5.3 v8 which is a pretty popular choice for the average buyer or if its also equally represented problem with the 6.2 v8 and the 4.3 v6

 

my though process has concluded its in the tranny since that is the only thing they have not tried replacing yet and there seams to be as though its temperature related such as the oil warming up in the tranny since when the truck is driven a few miles it begins to be more noticeable and people up north report it gets worse at certain temperatures

Posted

Could be as easy as the tune they have for the tranny. Used to tune LS series cars and recently stopped 2 years ago. My buddy that had a similar problem with his 08 vette that was supercharged. He had vibrations only at 40mph. The issue was the line pressure and the fuel mapping. Any trucks that have been tuned having any issues?

Posted

Question: I have the dealer installed, soft cover/tri fold tonneau cover. Does anyone think that could lend itself to any downward force and increased shuttering on this truck at highway speeds?

 

 

Sent from my iPhone

Posted

Question: I have the dealer installed, soft cover/tri fold tonneau cover. Does anyone think that could lend itself to any downward force and increased shuttering on this truck at highway speeds?

 

 

Sent from my iPhone

 

no

Posted (edited)

When people post can you please give us more info on the truck like make, model, type ( crew cab etc), 2wd or 4wd, rim size and brand of tire, month and year it was built. maybe we can narrow down which style is more of a issue or maybe it's just hit and miss on all styles

If everyone would go into their profile settings and insert their vehicle info it will show up under their profile name on the left side of the screen when they post something.

 

Edit: like mine is

Edited by 14LTZZ71
Posted

Could be as easy as the tune they have for the tranny. Used to tune LS series cars and recently stopped 2 years ago. My buddy that had a similar problem with his 08 vette that was supercharged. He had vibrations only at 40mph. The issue was the line pressure and the fuel mapping. Any trucks that have been tuned having any issues?

 

I'm curious about this as well. I'm pretty sure some of the guys with tunes here are saying they're trucks are vibration free. But I don't know of anyone that has had a vibrating truck and reported it, then got a tune and the vibration went away.

 

fondupot isn't your truck tuned? Yours has been vibration free as well right?

 

I agree the only thing left is the transmission at this point. That's the only thing that hasn't been changed outside of the tire replacements and the rear ring and pinion replacement that have fixed some. My question though is if you drop the transmission into neutral and it still vibrates, wouldn't that rule out the transmission?

Posted

I told the story to one of my friends, he spoke to his GM Mechanic buddy who said the issue is the transmission. But there is no fix yet.

 

Also related to the transmission, is when I am at a full stop and give it some gas, my transmission lags and then pops into gear. So irritating, makes me want to use the Manual mode with my thumb as the shifter instead of using my AUTOMATIC TRANSMISSION!!!

 

I suggest everyone, file a BBB complaint on your vehicle.

Posted (edited)

It sounds like the vibration issues could be a result of the trucks mechanical system resonance coinciding with a specific vehicle speed range. This vibration can occur independent of component balancing (ie; all rotating components such as drive shaft, tires, rotors, etc. either being balanced individually or as an assembly)

 

Here are two good articles further explaining this phenomena.

 

http://www.pump-zone.com/topics/motors/motor-and-drive-system-resonance-problems-and-solutions

.

http://www.wired.com/2010/03/flutter-testing-aircraft/

 

How is the vibration when you drop the transmission down into 5th gear or even 4rd gear? I would expect a definite increase or decrease in vibration levels.

 

Also wondering if the engine is being slightly overloaded and shuddering just enough to induce vibration at these highway speeds due to the final gear ratio in the transmission w/ overdrive.

Edited by 97SierraSLT
Posted (edited)

I told the story to one of my friends, he spoke to his GM Mechanic buddy who said the issue is the transmission. But there is no fix yet.

 

Also related to the transmission, is when I am at a full stop and give it some gas, my transmission lags and then pops into gear. So irritating, makes me want to use the Manual mode with my thumb as the shifter instead of using my AUTOMATIC TRANSMISSION!!!

 

I suggest everyone, file a BBB complaint on your vehicle.

That is what was happening to my truck, it felt like the tranny was not engaging at times.

This also happened while I was turning against traffic, I can not trust this vehicle will go when crossing high volume traffic.

I have been saying all along that the transmission is loosing pressure, and or leaking inside at pump.

This clearly explains why some people have notice different symptoms according to how temperature, load, and speed factor in on this shaking loss of pressure tranny!

This is my humble opinion, and nothing else that anyone has tried truely fixed or repaired it.

Some folks complain after 17,000 miles that this shaking started, this my friends rules out a lot of items, and points to tranny seals starting to leak and drop loss pressure causing shuddering which is felt from the driveline to the body as a shaking feeling.

This is going to be a big issue for GM and owners if trannys need to be pulled for repair, this is why they are saying nothing found, working as designed.

good luck my friends as a buy back would be the best action!

Edited by 2strokesmoke
Posted (edited)

This link will show you documented issues with Transmission, truck rolling backwards while in park, lag in tranny, engine turning off while driving, truck catching fire, headlights that don't aim at the road, and more. I am now more worried than before.

 

his link will take you to a relevant National Highway Traffic Safety Administration (NHTSA) Safety Issue page:

http://www-odi.nhtsa.dot.gov/owners/SearchResultsByUrlCode.action?referenceSearch.requestId=33960&referenceSearch.urlCode=RWRYQDLMAD8ZA7E

Edited by wagattack
Posted

I found another link with more alarming news. This lists all of the recalls for the GMC 2014 Sierras.

 

Loose fitting in transmission hose, airbags that fail to fully deploy but spit out the white smoke instead, seat brackets that are not welded properly, steering locking up, etc.

 

This link will take you to a relevant National Highway Traffic Safety Administration (NHTSA) Safety Issue page:

http://www-odi.nhtsa.dot.gov/owners/SearchResultsByUrlCode.action?referenceSearch.requestId=33959&referenceSearch.urlCode=174X12GEIWY650Z

Posted

Hi I have a 2014 sierra reg cab 4.3 2wd, tires general grabbers 255/70-17 build date 6/14...1721 miles. noticed vibration at 65 miles, called dealer they said it was due to flat spots on tires from sitting on lot..drive it and it would go away. Dropped off at dealer last evening, they called today said they balanced all 4 wheels..3 different people road tested.. vibration gone. I drive 2 miles from dealer.. vibration still there. Called dealer and talked to serv adv. I told him I felt it was in drivetrain ..so now I go back Fri for a drive with "service manager". But after talking on phone for a while he did tell me this is a very common problem and he cant recall any being repaired yet. Said gm is aware of problem..but no tsb has been released so far. I thanked him for his honesty,and will return for road test with mgr.

Posted

I just joined this site after reading through all of this and feeling I needed to reply to answer some questions. I have a 2014 SIlverado 1500 Crew LTZ 2WD Short Box with 6.2L Engine and 3.73 MAX TOWING PKG. with approx. 8000 miles. I had after market 22" wheels & tires installed from the start. I also added dual catback exhaust, CAI, did a custom dyno tune and installed an aftermarket 2 pc. high speed balanced driveshaft (for reasons other than the shimmy). My truck has always had the shimmy that starts between 60 & 65 and remains from there on up. It seems worse when towing my boat. I have tried putting the truck in neutral while it is doing it at 70 and no change. I had the tires rotated for the first time a few days ago and the shimmy didn't move, so I don't think its the tires or wheels. The putting in neutral doesn't necessarily rule out the tranny because there are still parts rotating. IMO, it would rule out a motor mount issue because the engine comes to idle when shifted to neutral. I will stay tuned in here until the problem is resolved. GREAT SITE!

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