Shake or Vibration Issues

[2strokesmoke]

I still feel this is a shifting issue, caused by gm's strick attempt to get every possible fuel mileage numbers.

In their attempt to achieve this they are holding the torque converter lock up longer and at lower speeds causing vibrations at some speeds throughout the 4th 5th and 6th gear range.

Torque, centrifugal force, weight, bad machining, combined to cause this problem.

Just my 2cents worth.

[2strokesmoke]

That is why bad tire issues are compounded during some speeds, correcting the tires making them perfectly balanced will help, but will not remove the real culprit. Another thought might be harmonic beaming coming from the driveshaft could be a factor as well.

Didn't someone post that gm has a new driveshaft design now, anyone know the new part number I would like that information anyone?

[pm26]

I still feel this is a shifting issue, caused by gm's strick attempt to get every possible fuel mileage numbers.

In their attempt to achieve this they are holding the torque converter lock up longer and at lower speeds causing vibrations at some speeds throughout the 4th 5th and 6th gear range.

Torque, centrifugal force, weight, bad machining, combined to cause this problem.

Just my 2cents worth.

I wish some tuner would come up with a simple fix for this. Let's face it, who here with vibration issues would not sacrifice 2 MPG to have a great running vibration free truck?

[MJFlores]

For what it's worth, here's something I tried today. And again, I have my vibration starting at 71mph on up so... In my mind, the rear end, drive shaft, and transmission dont really know what actual speed the truck is moving at...they only know RPM. I used tow mode on a smooth back road to similuate highway speed at RPM but at a much slower speed and I didnt experience the vibration. The truck has to be moving a certain speed, regardless of RPM. In my mind, this points to tires, rims, rotors, and hubs right? And of course, this slow speed test removed any mischief with air turbulence.

Edited April 30, 2014 by MJFlores

[hotrodz37]

For what it's worth, here's something I tried today. And again, I have my vibration starting at 71mph on up so... In my mind, the rear end, drive shaft, and transmission dont really know what actual speed the truck is moving at...they only know RPM. I used tow mode on a smooth back road to similuate highway speed at RPM but at a much slower speed and I didnt experience the vibration. The truck has to be moving a certain speed, regardless of RPM. In my mind, this points to tires, rims, rotors, and hubs right? And of course, this slow speed test removed any mischief with air turbulence.

 

The driveshaft and rear end gears move at wheel speed (if I'm not mistaken, and if I am I do apologize) and aren't dependent on the rpms of the engine. Good idea to test though to try and take one less factor out, might have ruled out the Torque Converter or a few other transmission related things.

Edited April 30, 2014 by hotrodz37

[pm26]

 

The driveshaft and rear end gears move at wheel speed (if I'm not mistaken, and if I am I do apologize) and aren't dependent on the rpms of the engine. Good idea to test though to try and take one less factor out, might have ruled out the Torque Converter or a few other transmission related things.

The driveshaft moves at speed of the wheels times the axle gear ratio. If the axle ratio is 3.42, then the driveshaft will turn 3.42 times per every revolution of the rear wheels. The rear axle pinion shaft and gear moves at the same speed as the driveshaft. The ring gear moves at the same speed as the wheels.

[20SierraL8T24]

Rear end in and... SAME exact vibration at highway speeds... I'm about done with this truck...

[Silverado-Hareek]

Rear end in and... SAME exact vibration at highway speeds... I'm about done with this truck...

How bad is the vibration you are experiencing? How would you describe it?

[20SierraL8T24]

Exactly like a rear tire that's out of balance... only between 74-78 mph and its driving me crazy

[Silverado-Hareek]

Exactly like a rear tire that's out of balance... only between 74-78 mph and its driving me crazy

Sorry you have to deal with that man. Keep us posted on what happens.

[pm26]

Exactly like a rear tire that's out of balance... only between 74-78 mph and its driving me crazy

Have you tried rotating the front tires to the back to see if anyhting changes? Years ago i had a tire with a shifting steel belt on a car and it was vibrating bad. When I rotated the tires, vibration markedly decreased and it was now in the back (originally felt in the steering wheel). This is how I found a bad tire. It was balanced right, but it still caused vibraiton because the steel belt was loose and the hotter the tire got the worse the vibration became.

Edited May 1, 2014 by pm26

[MJFlores]

Have you tried rotating the front tires to the back to see if anyhting changes? Years ago i had a tire with a shifting steel belt on a car and it was vibrating bad. When I rotated the tires, vibration markedly decreased and it was not in the bac (originally felt in the steering wheel). This is how I found a bad tire. It was balanced right, but it still cuased vibraiton becuase the steel belt was loose and the hotter the tire got the worse the vibration became.

I'm definately noticing much smoother ride at highway speeds in this coolder weather we've had the past few days. Last week temps were in the 70's, so my tires were showing around 38lbs after HW driving the vibration was the worst it had been. I wonder if I dont have a steel belt issue in one or both rear tires. Here I am with 4300 miles on a new truck and I'm thinking of buying 4 brand new tires from another place. Not cool.

[Silverado-Hareek]

I'm still keeping an eye on mine. I feel like there's a slight vibration that increases with the temperature as well. I didn't notice anything back in February but lateley I feel a slight vibration. I just can't tell if it's actually something new or I'm just paying attention to it more after reading this thread. I think I might bite the bullet and pay for an alignment and balance like my side mechanic recommended from the start on any new Chevy truck/SUV.

[Silverado-Hareek]

You guys think it might have anything to do with the new mounts/bearings that isolate the cabs from the frames on these trucks? Just brainstorming here.

[Silverado-Hareek]

Came across this explanation doing some google research: http://www.justanswer.com/chevy/29lyw-silverado-that-issuing-vibration-cab-mount-supresses.html

 

If this explanation is correct then it makes sense why Chevy won't address the issue....it's the physical design of the truck and not just this body style.