Shake or Vibration Issues

Bowtie619 · March 4, 2016

Ok guys, reporting back as promised. Drive shaft went on with no problems. It came with new Ujoints and yoke to slide in. So very easy to install as it came all in one piece...I don't want to jump the gun here because I only drove down a back road but I hit 70mph. USUALLY the second I hit 60mph I start to vibrate and it stays steady unless I push out to 70-80 and its much less at that speed. Well...it was GONE! I was screaming for joy in my truck when I hit 60-70 and no vibration!! Like I said...I still need to get on the freeway and do more testing but the first test drive was a complete success!!! I will note that I also put on my Magnaflow exhaust (Which sounds amazing) so I don't know if that could have changed anything (highly doubt). I'll get back to you guys after I do more driving. Today was a good day!! (Ice Cube Voice)

Edited March 5, 2016 by Bowtie619

Jamesandrew4 · March 5, 2016

So my service director is stating that they have hooked the vibration testing machine up to my truck. They stated that there are no spikes in the graph and that they do not see anything that gm would advise them to do work on. I am going to be taking a ride with the technician on Monday. I asked them to balance the rear drive shaft, they didn't do it. I told them about shimming the engine 3mm, I told them about the rear leaf springs and nothing. Getting frustrated!

Edited March 5, 2016 by Jamesandrew4

FLGMC · March 5, 2016

I purchased a 2016 2500hd GMC 6.0 L gas. i have a vibration issue in the gas pedal, steering wheel. The dealer had the truck for a week. He installed new motor mounts and some type of weights to the exhaust pipe. Has lessened to problem for now, I am not sure this has solved the problem. My question is does this occur with the diesel trucks?

pm26 · March 5, 2016

I purchased a 2016 2500hd GMC 6.0 L gas. i have a vibration issue in the gas pedal, steering wheel. The dealer had the truck for a week. He installed new motor mounts and some type of weights to the exhaust pipe. Has lessened to problem for now, I am not sure this has solved the problem. My question is does this occur with the diesel trucks?

I test drove a new 2015 HD2500 Sierra crew cab 4X4. 6.0 gas engine recently, I did not like the way the truck rode. There was a hint of vibration in the steering wheel even at 45 MPH, the steering wheel was off center when going straight. It is enough to say that I did not buy the truck. It could have been something minor but I will not take any chances. And I am not even considering any new GM truck until I see a positive proof that they have fixed these issues and instituted decent quality control. As for diesel trucks having these vibration problems - some do, as evidenced by some complaints of this type on the HD forum.

As for the "exhaust pipe weights", what exactly are those? Perhaps they help alleviate exhaust system vibration?

Edited March 5, 2016 by pm26

FLGMC · March 5, 2016

The Shop Forman said they were GM Certified parts? Not sure, looks a little odd?

paxtonman · March 5, 2016

I am very close to purchasing a 2014 sierra rcsb. i love the look of the truck inside and out, my secondary option is the ram with the 8speed but frankly i like the gm design better.

I stumbled across this thread in my research and 550 pages have me worried. knowing how many of these trucks are sold overall is the consensus that the shakers are the exception and there are fine examples quietly out on the road?

Do you think a thorough test drive would show these problems and this headache could be avoided by choosing a good driver? I intend to keep the truck i buy as long as possible so would hate to run into this issue down the road.

Basically i thought i was all set to purchase my new/used truck but now i'm second guessing myself, please help.

I would not buy one of these used.

Wrench589 · March 5, 2016

Stiffness of suspension is usually dictated by stiff springs. But very stiff shock absorbers will cause a rough and stiff ride over uneven surfaces even with softer springs, which is probably the case here.

Stiff shocks simply rebound too fast and they do not allow for full movement of the springs to absorb the road shock. Shock absorbers actually do not absorb shock at all - springs do. "Shock absorbers" simply dampen the spring oscillations.

Actually, the shocks don't rebound. The suspension spring is attempting to rebound and the shock resists that due to its dampening. Most shocks provide dampening in both the compression and rebound motion.

As mentioned, the suspension stiffness is done by the springs. That is essentially fixed for a given spring. The shocks provide the damping, which is essentially resistance to movement. Sounds the same as spring force? Well, it's not.

Here's the best way to understand the difference. The spring rate dictates the force, so many lb of force per in of deflection. That is the same whether compressing the suspension slowly or quickly. However, the force residing movement of a damper (shock absorber) is greatly affected by the speed of motion. Apply the movement very slowly, and the shock will move with very little resistive force. But try to move it quickly, and it almost locks up! This is essentially frictional resistance, as the fluid tries to get through the tiny orifice holes in the shock.

Now, don't be confused by the fact that most modern shocks are gas charged, and seem to excited spring-like ability. The gas charge does give the shock some amount of "springingness" and they will fully extend themselves but the amount of force is minimal in comparison to the suspension spring itself. Now, the gas s not there for spring rate, it's there to keep the oil from cavitation (bubbling) as its forced through the orifices inside.

High end and competition shocks are adjustable. That means the damping rate (or friction generated) is adjustable. This is usually done by some kind of adjustable orifice (ie valve) on the outside of the shock that the user can adjust. Some have compression adjustment, some have rebound adjustment, and some both. The electronically adjustable shocks on the GMs do this adjustment from the computer multiple times a second, as per the program.

As pm26 indicated, the entire function of damping is to absorb the natural oscillations of a spring that would occur if there was zero friction (damping) present. And as he said, shocks with excessive damping will provide excessive resistance friction to even small/slow suspension movements and this will make the suspension feel stiff. But it's not the same stiffness as stiff springs. Still makes for a hard ride, either way. Many folks do refer to shocks as having stiffness (he put stiffer shocks on his sports car...) but as I'd explained, it's really not stiffness in the classical sense (lb/in).

abominable z71 · March 5, 2016

The best way to think of the shock itself is as a brake for the movement of the spring. Kinetic energy is ultimately converted to heat via friction and dissapated to the atmosphere. Gently apply the brakes and the car comes to a stop nice and smooth over a long distance. Slam on the brakes and you quickly test the lock mechanism on the seat belts. I've talked to fox, king and radflo and they all say the same thing it's not a stiffer ride it's "firmer" lol. Stiff carriers a very negative connotation in the suspension world but firmer implies performance, semantics at work. I've got the rs9000 adjustable shocks all the way around. The lightest setting lets the spring travel further with input and "feels" softer, the trade off is degraded handling and an increase in body roll. one thing for sure, it doesn't matter setting 1 thru 9 the vibration is always the same.

Snoringbear · March 5, 2016

I just want to say that my 2015 Denali vibrated stock. The vibration always felt like it was coming from the passenger front tire.

It vibrated after balancing tires. After rotating the tires to put max RFV max on back tires and min at front passenger.

It vibrated after a 2 in lift / level kit in the front (with sensor adjustments to compensate for added distance between sensor and angled upper a-arm)

It got a little better after I added leaf spring clamps in front of the axle. But in order for them to work without interfering with sensors, it had to be too far forward and lowered the rear of the truck a little.

It still vibrated after and alignment done by independent shop.

It still vibrated after I added a 2.5 inch add-a leaf (with sensor adjustment to compensate for added distance between frame and bracket on axle)

It vibrated after I reinstalled the leaf spring clamps to the rear of the axle but closer than before when I put them in the front. The rear of the truck lowered about .5 inch (lift was now 2inches) and vibration was maybe a little better.

It vibrated after I got a second alignment.

It got a lot better when I started tweaking the toe-in to spec myself using the front tie rods and a tape measure.

It has almost completely stopped vibrating when I got a third alignment where they adjusted the caster and camber on the passenger's side.

Sometimes it comes back though. So we shall see. Today the temp was above 50 degrees. The truck seems much tighter/rougher below 40 degrees.

Also I'd like to say that I can't believe this thread is 552 pages with over 8000 posts. That is an incredible problem that GM has with these trucks.

I wouldn't get caught up in the absolute number of posts. I think the 90/10 rule may be applicable here - meaning over 90% of posts are made by less than 10% of posters. Example; check out the number of posts made by pm26.

Jed Blanks · March 5, 2016

I wouldn't get caught up in the absolute number of posts. I think the 90/10 rule may be applicable here - meaning over 90% of posts are made by less than 10% of posters. Example; check out the number of posts made by pm26.

Hmm. Ok. So 10%. Of 8200 is 820. But then wouldn't the 90/10 rule also apply to the number of real world people with this vibration vs the number of people that post here,

Heck lets go ahead and say 1 out of 100 people with the problem post here.

That gets us to what? 82000 issues?

And based on the efforts of those offered replacement trucks, it sounds like 90% vibrate. It usually takes 5-10 before they find one that doesn't.

How many did they make? 800,000?

Edited March 5, 2016 by jblanks

Binobanbino · March 5, 2016

Just wanted to let you guys know. Don't waste your time calling GM. At first they show you that your issues is a great concern to them. After they try and repair your truck and they have a Final attempt to fix it no matter how the truck comes out vibrating or not they will say it is fine.

I took my truck to the dealer the GM engineers drove a saw that it was shaking ask the dealer to perform the necessary repairs after that they left never drove the truck again but yet they an email to the dealer saying the truck is fine.

So the local dealer not to go against GM orders they wrote on the paperwork that the truck was fixed to spec. They told me that the truck was ready to go I went to pick it up I test drove it with them and they stay it's still shaking. But they can do nothing about it.

That tells you something here about this issue. They know their truck shake. They don't care if the customers complains as long as they get their money that's all that matters. So if you want to go on here and tell me different go right ahead. I know what happends I just went thru it.

Like it or not this is what GM dose.

pm26 · March 5, 2016

I wouldn't get caught up in the absolute number of posts. I think the 90/10 rule may be applicable here - meaning over 90% of posts are made by less than 10% of posters. Example; check out the number of posts made by pm26.

Yes, and I have been posted in this particular thread since 2005, just as soon as I joined the gm-trucks forum.

Edited March 5, 2016 by pm26

Snoringbear · March 5, 2016

Yes, and I have been posted in this particular thread since 2005, just as soon as I joined the gm-trucks forum.

That's a long time to pound sand. Why don't you just move along and buy a Ford or Ram? Try getting a life ?

C6Bill · March 6, 2016

Or a Tundra, go buy a Tundra, I love my mine. Don't miss my Chevy's at all.

But I just can't stop watching this train wreck of a thread. Still feel bad for all of you stuck with these vibrators. Too bad GM couldn't care less if you like your trucks or not, they got your money. Now they will just sit back and wait for the next sucker to walk through the door.

And anyone who would even consider buying a 14 or 15 after reading this thread .....I have some nice ocean front property to sell you in Nebraska.

Why do you think the used lots are full of these things with extremely low miles ??? Yup, they sure do look good and the price is fantastic for a 1 or 2 year old vehicle. But there is a real good chance you will be right back here trying to figure out why GM won't fix your truck.

pm26 · March 6, 2016

If a state lemon law allows one to force the GM to buy back their vehicle if it cannot be fixed after so many attempts, why isn't there a similar law that would prevent GM from selling the same vehicle, in the same condition as a "certified used vehicle" to another unsuspecting customer through their dealers? Don't they have to disclose that this vehicle is a former lemon buyback and that nothing has been done to it to correct the defect?

Edited March 6, 2016 by pm26