Shake or Vibration Issues

[Darth_Vader]

I guess there is a lot of people who do not understand the meaning of frame beaming! It is a transfer of energy across a lintel of steel...in this case a trucks frame.

Nothing is wrong with the frame! It just transfers energy very well, which is then felt throughout the cabin.

 

 

Exactly, the issue isn't the frame, the issue is elsewhere and is being transmitted. But it is a fixable issue, it just happens to occur for different reasons.

[pickmeup]

Surprised GM did not pick this up in mule testing of k2xx platform long before 2014 release . Or maybe they did and decided to proceed anyways .

[PMurray]

your explanation sounds plausible! What I was trying to say is by placing a clamp in front of leaf springs, this causes the vibrations to be absorbed over more of the leafs. I used the word density, a more suitable word would have been more "volume+density". More metal volume or density for energy to be absorbed. This energy is either from the engine, driveline, road force which you feel as vibrations into the cabin. Pinion angle may be improved, but that is not the real problem, the transfer of energy is!

Thxs

I believe the term that you want is "mass."

[Wrench589]

I guess there is a lot of people who do not understand the meaning of frame beaming! It is a transfer of energy across a lintel of steel...in this case a trucks frame.

Nothing is wrong with the frame! It just transfers energy very well, which is then felt throughout the cabin.

Actually, "frame beaming" is not about energy transfer. It's a lay-person term to describe the frame natural frequency being excited and the result is a resonant condition. The reality is, every frame is going to have a natural frequency. In fact, many may have multiple "modes" of natural frequency. Depending on the amount of inherent damping in the system and the available excitation forces/frequencies, the frame modes may or may not be excited into a resonance.

 

This is quite obvious based on GM's TSB on frame beaming in previous generation trucks when the TSB notes that a significant amount of mass in the box will change the response of the "frame beaming". Simple vibration theory, where the natural frequency of a beam (the frame in this case) is a function of the stiffness and the mass. Changing the mass will change the natural frequency and hence "de-tune" the resonance. Simple. We use that principle all the time to de-tune machinery vibrations. Of course, who wants to haul around 1000 lb of sand bags in their 1/2-ton all the time!

 

All that said, I believe several owners have reported that hauling some weight in the back of the truck really did not change things much. Tells me it's NOT frame beaming.

 

Regarding vibration transmission, that's an entirely different topic.

Edited February 26, 2017 by Wrench589

[2strokesmoke]

Actually, "frame beaming" is not about energy transfer. It's a lay-person term to describe the frame natural frequency being excited and the result is a resonant condition. The reality is, every frame is going to have a natural frequency. In fact, many may have multiple "modes" of natural frequency. Depending on the amount of inherent damping in the system and the available excitation forces/frequencies, the frame modes may or may not be excited into a resonance.

This is quite obvious based on GM's TSB on frame beaming in previous generation trucks when the TSB notes that a significant amount of mass in the box will change the response of the "frame beaming". Simple vibration theory, where the natural frequency of a beam (the frame in this case) is a function of the stiffness and the mass. Changing the mass will change the natural frequency and hence "de-tune" the resonance. Simple. We use that principle all the time to de-tune machinery vibrations. Of course, who wants to haul around 1000 lb of sand bags in their 1/2-ton all the time!

All that said, I believe several owners have reported that hauling some weight in the back of the truck really did not change things much. Tells me it's NOT frame beaming.

Regarding vibration transmission, that's an entirely different topic.

Very well written!

Resonance is a constant, controling it is a balancing act. Stronger metal, but lighter frames is a challenge now for many auto manufactures to reduce the energy from drivelines and engine. If the engine and driveline was releasing vibration energy, a heavier mass frame would absorb this energy therefore it cancelling out the vibration.

 

One theory I will offer up here is a torque converter issue as well! GM knows about this ongoing issue as well.

The "engine lugging" theory, low rpm and a locked up transmission to engine causes resonance, vibrations into the vehicle. Not to rule out poorly machined parts that creates a stacking vibration effect!

 

Thxs

[1997SierraSLT]

I've followed this topic from day one and I have not seen anyone do an experiment by loading up the truck bed with a significant amount of weight (1000 lbs worth of concrete bags for instance) to test whether or not vibration is better or worse. This amount of additional mass would not only change the resonant frequency of the structure but also driveshaft pinion angles and suspension geometry.

 

Well.....wrench589 just beat me to it

Edited February 26, 2017 by 97SierraSLT

[polarys425]

I've followed this topic from day one and I have not seen anyone do an experiment by loading up the truck bed with a significant amount of weight (1000 lbs worth of concrete bags for instance) to test whether or not vibration is better or worse. This amount of additional mass would not only change the resonant frequency of the structure but also driveshaft pinion angles and suspension geometry.

 

Well.....wrench589 just beat me to it

 

I know I've posted that adding weight to mine eliminates the minor vibe I have that occurs at 75mph. In my case it's just a few hundred pounds. Do I have an exact weight? No.

[trik396]

I routinely have approximately 500 plus pounds in my bed. Sometimes probably closer to half a ton. Does nothing for my vibration

[14silverado4.3]

I am wondering if the highway vibes are occuring during "lockup" and is "lockup chatter".

 

If I tap the brakes at 74 mph when I have the vibration, it goes a way for a second but then it seems to come back fairly quickly. Is the TC unlocking and locking up that quickly?

 

I do not believe it to be a tire, because there are good days and bad days, a tire would be all the time.

 

I have 55000 miles and am not throwing codes, will chatter throw a code? What should I push GM to look for to determine if it is chatter / TC failure? Any other symptoms I would experience? My transmission fluid is a pinkish grey about a 50/50 appearance.

[abominable z71]

Surprised GM did not pick this up in mule testing of k2xx platform long before 2014 release . Or maybe they did and decided to proceed anyways .

The problem with mules is so few are made the parts they are built from are held to much tighter tolerances. It isn't til mass production that components pushing the edge of the tolerances are made and then you find your issues. It's a problem inherent in prototyping you can't catch issues that will arise during mass production. However; GM should have figured it out well before the 2015 MY runs considering this issue popped up in late 2013. Which is why many speculate they know what causes it but the fix was too much money.

[grizz_wi]

Got mine back, after sitting waiting for 2 hours they replaced a front tire and sent me on my way. I didnt feel like highway driving after waiting that long so I'll know tomorrow, but im betting its still there

 

Edit: Nope still there, console rattles, water bottle shakes like crazy, they didnt even test drive it, sigh..

Edited February 28, 2017 by grizz_wi

[Snoringbear]

Surprised GM did not pick this up in mule testing of k2xx platform long before 2014 release . Or maybe they did and decided to proceed anyways .

Speaking of Mules, here's a Truck Trend article about 2019 Sierra.

 

http://www.trucktrend.com/future-trucks/1702-spied-2019-gmc-sierra-1500-testing-in-southern-california/

[abominable z71]

I've followed this topic from day one and I have not seen anyone do an experiment by loading up the truck bed with a significant amount of weight (1000 lbs worth of concrete bags for instance) to test whether or not vibration is better or worse. This amount of additional mass would not only change the resonant frequency of the structure but also driveshaft pinion angles and suspension geometry.

 

Well.....wrench589 just beat me to it

Some people have said towing a trailer or having a decent load in the bed like an ATV/snowmobile actually makes the vibration worse.

[Jsb55]

I had a 2014 Z71 crew cab 4x4 Silverado 1500 that drove awesome!! No vibrations, transmission great and was happy. My wife has the same in a GMC and is great also. Well with all the rebates going on I decided to trade in for a 2017. Same truck just with different tires and I have the dreaded vibration starting at 72 and ridiculous at 78mph. Going in the shop for road balancing today.

[14silverado4.3]

I had a 2014 Z71 crew cab 4x4 Silverado 1500 that drove awesome!! No vibrations, transmission great and was happy. My wife has the same in a GMC and is great also. Well with all the rebates going on I decided to trade in for a 2017. Same truck just with different tires and I have the dreaded vibration starting at 72 and ridiculous at 78mph. Going in the shop for road balancing today.

It sucks, if it cant be resolved push for a buy back