vibration

[budone]

Originally Posted by slacker_53

How about getting the driveshaft balanced, or at least checking the balance?

Tuesday my 2005 is going in for the 6th time for this vibration. After three balancings in 2000 miles (That I had to pay for) and a U Joint's being replaced, (this actually made it worse) I was FINALLY able to get someone at the dealership to notice it.

The truck vibrates between 52-70. But at 62mph it is not only vibratiing but resonating through the truck.....

Since day one I have said it is either the tranny or transfer case. (But hey, they are the experts.) I personally still think it is one or the other.

[GMMerlin]

OK guys I may be the bearer of bad news you may not want to hear.

On these trucks there is a a sensation called "frame beaming" that can be felt between 50-70 mph...this is a normal condition and there is a GM Technical bulletin regarding this condition.
In a nutshell your truck was designed to be used as a truck (you know carry, tow and haul stuff). When it is driven unloaded this sensation is prevelent.
The bulletin has a diagnostic procedure to drive the vehicle unloaded with an Electronic Vibration Analizer and note the frequency of the vibration. If the frequency falls within a certain range, the next step is to add approximately 500lbs of weight to the vehicle and reroadtest it again. If the vibration is not present with weight in the vehicle then this is a normal operational characteristic of the vehicle and no repair attempts are to be taken.
The sensation you are feeling is most likey more noticable when you are driving on concrete surfaced roads..the reason for this has to do with suspension geometry, driveline angles, wheelbase and the harmonics of the vehicle tires hitting the expansion joints of the road surface.
With no weight in the vehicle, there is nothing to dampen these vibrations and they will transmit into the passenger compartment.
Now before you start argueing with me about this, I own one of these vehicles and have felt this sensation with my vehicle..most noticable at highway speeds on concrete surfaced roads with the truck unloaded.
Since I have loaded my inbed toolbox with my carpentry tools (about 300-400 lbs of weight) I have not felt this sensation.
My advise to you is this.
If you are feeling this, it may be a normal characteristic of your vehicle so be prepared to hear this from the service department.
But, make sure that the service department does a bulletin search and that they drive your vehicle with the Electronic Vibration Analizer to insure that there are not any addressable vibrations on your vehicle.
The EVA is a essential tool that all GM dealers should have in the service department and there are service and diagnostic procedures in service information in regards to vibration diagnostics.

[budone]

Originally Posted by budone

Tuesday my 2005 is going in for the 6th time for this vibration. After three balancings in 2000 miles (That I had to pay for) and a U Joint's being replaced, (this actually made it worse) I was FINALLY able to get someone at the dealership to notice it.

The truck vibrates between 52-70. But at 62mph it is not only vibratiing but resonating through the truck.....

Since day one I have said it is either the tranny or transfer case. (But hey, they are the experts.) I personally still think it is one or the other.

Update to my situation. I noticed this weekend, if I place the truck in 4WD or 4Auto, the vibration and the roar disappears and is actually a much smoother ride than in 2WD. But no, I do not keep in 4WD.

[Trucks_n_Harleys]

hmmmmmm...Funny, no other truck I've driven does this...Not even an old 73 dodge ext cab full lenght bed truck that was not even "technically" designed....or not as much as the ones we are here for on this board....

I have noticed that the carrier bearing housing's " RUBBER" bushing allows the 2 axles move a 1/2 inch within the housing....Thats not right and is to much movement...when I get the $'s to replace I will post results....


Also...Those who post this thread, state if your driving a reg cab or ext cab....

[budone]

Originally Posted by Trucks_n_Harleys

Also...Those who post this thread, state if your driving a reg cab or ext cab....

Mine is an extended cab 2005 Silverado Z71.

It will be interesting, at least to me, to see what they do. Chevy did receive my 'Last Chance Letter' concerning the truck before going towards a lemon Law resolution

[budone]

Update on my Vibratarado....

The truck went in today and they were to keep it until it is fixed.

Well. they used a TSB to say they can not fix it. Dated June 28th 2005.

It is doc # 1679169.

The TSB addresses the noise in the transfer case and it disappearing when I place the truck in 4WD.

It does not address the vibration I now have at any speed since they replaced my U-joints........and at 57-65mph prior to the u-joint replacment....

Quality is job one????

Now to hear from corporate Chevy......ta

[ColoradoSilverado]

Never thought about it to mention before, I do a lot of hauling like dirt, rocks, mulch etc. And indeed the vibration is gone when loaded.
Hmmm,interesting.....

Bert

[GMMerlin]

Originally Posted by budone

Update on my Vibratarado....

The truck went in today and they were to keep it until it is fixed.

Well. they used a TSB to say they can not fix it. Dated June 28th 2005.

It is doc # 1679169.

The TSB addresses the noise in the transfer case and it disappearing when I place the truck in 4WD.

It does not address the vibration I now have at any speed since they replaced my U-joints........and at 57-65mph prior to the u-joint replacment....

Quality is job one????

Now to hear from corporate Chevy......ta

The Doc number you gave is not a bulletin, but a directive informing the dealer to establish an engineering case with GM for further investigation and a possible future repair which could come as a TSB.
Not all is lost..

[GMMerlin]

Originally Posted by Trucks_n_Harleys

hmmmmmm...Funny, no other truck I've driven does this...Not even an old 73 dodge ext cab full lenght bed truck that was not even "technically" designed....or not as much as the ones we are here for on this board....

I have noticed that the carrier bearing housing's " RUBBER" bushing allows the 2 axles move a 1/2 inch within the housing....Thats not right and is to much movement...when I get the $'s to replace I will post results....


Also...Those who post this thread, state if your driving a reg cab or ext cab....

Rubber mounted carrier bearings for an axle? Havent seen that on a GM vehicle

[ColoradoSilverado]

Originally Posted by slacker_53

How about getting the driveshaft balanced, or at least checking the balance?

I was just looking in my newly bought Haynes repair manual and it said to check if the weight(s) are stillon the driveshaft, where are these usualy located ? And how can I tell if it's outof balance ?

Bert

[budone]

Originally Posted by ColoradoSilverado

I was just looking in my newly bought Haynes repair manual and it said to check if the weight(s) are stillon the driveshaft, where are these usualy located ? And how can I tell if it's outof balance ?

Bert

I did ask twice to have the driveshaft balanced since they replaced the U-joints. I was told it was not needed.

I did have about 900# of dirt and sand in the turck this weekend. The vibration was not as bad, but it was definitely still there.....

[HanibalTheCannibal]

This is definitely a rotating mass problem is it not? Brake rotors get so little respect in vibration troubleshooting.

Ok, I am new to the chevrolet scene. I just put my first 2000 miles on an 01 silverado 2wd ext cab., I stumbled across this thread and I can't help but bring up one additional point of interest. But I am in now way new to mechanics, ALL previous vehicles were 1970's models

anywho, I had an annoying vibration problem on my truck, and after much review and money spent, I discovered the problem (in my case). It was the brake rotors. Yep, those shiny circular things that spin tirelessly and transfer your linear motion to circular motion, then to HEAT to slow you down. They get so hot, then you hit a water puddle "JUST ONCE" and they can go out of spec. Sometimes noticeable to the eye.

see: http://en.wikipedia.org/wiki/Metallurgy

So if its been a while since you packed your bearings with new grease, why not try it. You will need new bearing seals etc. then remove the rotors. Take em to a good machine shop and have them reground or "turned" . Some machine shops can tell you if they are balanced. They drill holes in various sizes and in various lenghts from center to acheive a good balance. I had a set of brand new rotors go so out of shape, I would not have believed it if I had not seen it for myself. SOmetimes having them turned will resolve the problem.
Just something to think about.

[budone]

Originally Posted by HanibalTheCannibal

It was the brake rotors. Yep, those shiny circular things that spin tirelessly and transfer your linear motion to circular motion, then to HEAT to slow you down.

Thanks for the advice, I thought I posted this before but I do not see it.

The rotors were turned at 9000 miles due to braking vibration. Then at 16,000 they were replaced for a braking vibration.

So the new rotors have been on the truck for less than 1000 miles.

[chuck16]

I have a vibration in my truck that begins right on acceleration at about 20 km.hr. I had all 3 u-joints replaced, and my drive shaft balanced. Still there. I've just put all new rotors on and that didn't make a lick of difference either. My next try is the shocks then new rear springs and if that doesn't fix it I'm going to get a set of Timbren Spring helpers.

I've been told 2 different problems with these truck.
a) The intermediate drive shaft on these units cause the drive line to shimmy no matter what you do. If you go to a 1 piece drive shaft the problem goes away.

b) Guys that have put spring assist or Air Bags on there truck that were suffering from this vibration have said that after the Air Bag or Spring Assist is installed the vibration goes away.

Sucks doesn't it....I also haven't had my tires balanced or wheels checked for trueness to see if that has anything to do with it as well...

Ev

[GMMerlin]

Well many good points have been addressed here.
As far as rotors and drums go in vibration diagnosis, there are 2 differnet vibrations you can get..a vibration caused by an out of balance or a vibration caused by excessive lateral run out (apply pulsation).
When describing a rotating vibration, any componant that rotates at the same speed as the tire and wheel assembly can cause a "tire related" vibration.
Brake vibrations are usually called pulsations, they occur when the brakes are applied.
Brake vibrations are caused by excessive lateral runout of the friction surface.
Lateral runout can be caused by improperly torqued lug nuts.

The rotors were turned at 9000 miles due to braking vibration. Then at 16,000 they were replaced for a braking vibration.

The reason for this was improperly torqued lug nuts and a pulsation occurs 3000-6000 after the lugs were tightened.

The intermediate drive shaft on these units cause the drive line to shimmy no matter what you do. If you go to a 1 piece drive shaft the problem goes away.

Some GM light trucks come with a 2 piece driveshaft, the working angles and phasing must be dead on to prevent vibrations.
Some of these concerns have been eliminated by installing a 1 peice driveshaft.

Guys that have put spring assist or Air Bags on there truck that were suffering from this vibration have said that after the Air Bag or Spring Assist is installed the vibration goes away

Some of the vibrations may be related to a launch shutter or spring wrap up.
By changing the suspension geometry, you can change the frequency of a vibration (the vibration is still there, just at a different speed or intensity)

I have a vibration in my truck that begins right on acceleration at about 20 km.hr.

This could be a launch shutter and by changing driveline angles it could be eliminated.
The pinion nose rises as the truck is excellerated this causes the driveline angles to change, by lowering the pinion nose 1/2 degree, you could eliminate the concern.