SierraRover

I suspect some folks have it and don't realize, and others have it to a minimal degree. Some may not have it at all! The cause seems to be the natural resonance (38 Herz) of the frame, raised to the level of human perception by drive train vibrations or wheel vibrations. Some people have success getting their dealer to diminish the vibration, primarily by balancing the wheels. I had no such luck, and in the end my dealer acted like "we cannot replicate the vibration" although I showed them a video of it! I sold my 2014 GMC with around 20,000 miles on it. Luckily, it brought almost what I paid for it, in the trade-in. I now have a 2017 Jeep Grand Cherokee -- the purchase of which was another triumph of hope over experience, in that my previous four Jeep Grand Cherokees -- going back into the 1990's -- had a series of perplexing problems (mostly electronic). But at least the Jeep dealers always tried to help me get them fixed, and in the end the vehicles provided good service. Bottom line, I'd take any new GMC truck out for an extensive test drive (highway speeds from 45-70) before buying it, to see what your luck of the draw might be. And I'd serve notice to them, this bear is coming back for a refund if it develops this vibration problem so many people talk about on the internet.

Shredzy is right. I posted some info on my experiences with the Morimoto kit a couple of pages back in this thread. A complete swap-out to a new headlight housing (2016+) would be difficult because the wiring is different -- and it would be very expensive. By the way, I sold my 2014 - loved the truck, but in the end the vibrations got the better of me. The headlights were a pain for quite a while until I added the Morimoto HID kit, and it worked very well indeed. But those vibrations... This is my last post. I am now driving a 2017 Jeep Grand Cherokee!

I fixed my vibration problem in my 2014 GMC Sierra. I traded it in on a new vehicle -- not a GM -- on 20 Aug 17.

The shaking cup video is at:

A lease is an option. If you lease a Sierra or Silverado that appears to have the "shaking" problem, you could almost certainly take it back on the lease and have them replace it. How many have this problem, and to what degree? I don't think anyone knows, but the odds are in your favor. Most people seem to be driving these trucks day to day without a problem. If you have the problem, it is hard to isolate and fix -- but a lease gives you a quicker 'out.' As for ownership versus leasing -- leases can be a good deal, but the key is to keep the mileage low. I essentially follow L86 All Terrain's model of car/truck ownership and agree it works for vehicles that retain re-sale value. For example, a truck. Anytime your total annual cost for owning a vehicle is below $5000 (USD) a year -- including gas, insurance, maintenance, depreciation, and taxes -- you are doing great.

It's true that the regular cab/short bed is a bumpy ride!

The comments in this thread make sense. I am NOT an engineer, but have read enough on this problem to think the basic vibration can come from tires, driveshaft, etc. Then the frame of the truck resonates, vibrating at 38-40 Herz, which is probably a harmonic of the basic source vibration. So balancing or even replacing tires is sometimes successful in solving or mitigating the overall truck vibration. And some GM trucks don't have a noticeable problem at all. My truck -- a short wheelbase, regular cab Sierra 1500 -- probably has may have less potential for vibration than a long bed -- because there is less frame length to flex, a shorter drive shaft, etc. But it still vibrates. I can live with it around town. This is terrible truck to take on a highway trip, however. The amplitude goes up the faster I go, but the rate of vibration (the frequency) stays the same. Sometimes it rises and falls in amplitude, creating almost a buffeting effect, perhaps indicating two sources or a source plus a harmonic of another source are reaching the frame at the same time. Here is a video of what it looks like at 68 mph: https://youtu.be/lYtORlwqddw

I expect to get a letter from GM in the next 30-60 days on this. It looks like a simple flash of the computer, but they have to get the update out to the dealers. The problem does not look like it is deadly, e.g., low speed, short-duration loss of steering boost. If you have one that you bought second-hand, and might not be on GM's mailing list of original owners, then just check back on the GM Recall web page in a month or so. This recall is annoying but not alarming. Now, the Takata airbag recall on my 2014 VW is alarming... replacement parts are not available, and probably won't be for a long time, and the older they get, the more likely they are to not work correctly... something like 1,000,000 vehicles have the same bad Takata airbag initiator in them...

The idea of a damper attached to the frame rails may have merit; it would take an engineer to figure out where and how to attach it. The rubber or polystyrene mounts between the body and the frame are another point where the vibration could possibly be isolated. Even a better seat mount could work wonders to cut the ability of the driver to perceive the vibration from inside the cab. GM reportedly is coming out with the GMT T1XX platform for pickups beginning in the 2019 model year. I am sure they will incorporate what they have learned with the K2XX platforms, and specifically with the K2XG platform of the Sierra. At least we can hope they will.

Picked up the vibrating 2014 Sierra 1500 from the dealer after tire rotation and balance. The dealer did not check the drive shaft like I asked them to do. The paperwork says "could not replicate" the vibration -- this after I showed it to them on a video during the write-up. Pointless to go back and argue with the kid at the service desk. Took the truck out to the expressway, ran it at 65, and it still vibrates like, well, a vibrator with fresh batteries. It's not very noticeable around town, where I do most of my driving. On the highway, it'll make you crazy. I like this truck, but... I had to install the Morimoto HID headlight bulbs to fix the dim OEM bulbs that GM built wrong in the first place and wouldn't own up to fixing... Now GMC cannot or will not fix the vibration. Not going to chase a lot of after-market solutions and do-overs at my own expense. The truck has held its resale value surprisingly well (78% according to KBB after three years!) so it's destiny may be to end up as a trade-in for a Ford F150.

Well, I've got the vibration issue in my 2014, made on the same YKXX frame as the new ones. It just resonates at around 38-40 Hertz, at speeds over 40 mph. Its in the shop again to try the tires/wheels solution (it has 21,000 miles). I don't know the percentages... but it is enough that I would not buy another one. It is otherwise a great truck. I would say you could venture to buy a new one... but give it a test drive on the interstate. And if you buy it -- lots of people report the vibration isn't there initially, but starts up after a few thousand miles -- be prepared to take it back to the dealer right away. Work that angle hard. And if they can't fix it in three or four visits, go for the buy-back or 'lemon law' buyout relatively early in the life of the truck. It won't get better by itself.

My 2014 is in the shop for the vibration right now. I took a video of a McDonald's cup just chattering away in the cup holder to illustrate. It seems to resonate at about the 38-40 Hertz rate when it gets to about 40 mph and upwards. I found an app on the internet (completely dis-related from cars) that shows a light flickering at 40 Hertz -- and that's pretty close to frequency at which my truck vibrates. Felt through the steering wheel and the seat; visible on the console. Lots of causes mentioned on the web -- tires, wheels, wheel flanges, drive shaft, etc. I believe the problem stems from the Y2XX K2XX platform, introduced in 2014, which apparently just resonates at that frequency, incited by any number of components that can vibrate locally. Sorry to say this is my last GM product, although I've always been a GM man.

Agree. A reason in favor of leases over purchase. GM has had a lot of recalls. They decided this issue wasn't worth fixing the right way. Shame on them, but they are so fat and sassy that they don't care if you or I buy (or lease) a Ford next time. But everyone reading this forum, who has this problem, should consider writing to the NTSB (or Transport Canada) on their web pages to register a safety complaint, and maybe consider writing to GM. Just for the principle of the thing. In the mean time, a good HID kit is a practical solution for owners. And not that hard to install.

The Vosla bulbs have a life of around 250 hours. Less if the voltage supply is higher than 13 volts. And don't forget that your bulbs are on all the time the engine is running. I agree that you shouldn't have to pay for a HID kit. GM really let down their customers on this one. I added the Morimoto HID kit to give myself better visibility of the road -- which it does very well. And incidentally to have bulbs that last longer -- around 2500 hours.

I installed the Morimoto HID kit from Retro Fit Source this weekend. https://www.theretrofitsource.com/2014-sierra-morimoto-elite.html It is great – the headlights light up the road now. They are 100% better than the OEM lights. I am waiting for a dark, rainy night so I can go for a ride on a country road. I will see the dark-clothed people that walk along the roadside, and laugh at the night. The Morimoto components appear to be top quality and the bulbs are rated for 2500 hours. We'll see how it holds up. The main challenge: The hardest part of the installation is figuring out where to place and anchor everything inside the front of your Sierra. Two things are not as depicted in the instructions: 1. The Capacitor does not have a separate line to Ground, although the drawing shows that it does. I don’t think this matters. 2. The connectors from the ballasts to the OEM power inputs (the line that went to the old OEM bulb) does not have the connector cap on it – just bare wires with end pins. That is necessary because the hole in the backing caps is 22mm, and too small for the caps to pass through if connected. So you have to install the caps yourself after pushing the pins into place. No problem – just connect the red wire to the positive side, and black to black, matching the line being connected into. One interesting feature: According to the instructions, you only hook up one of the OEM bulb input lines to the Morimoto harness. This one line is connected to your OEM headlight system and activates the new HID system. The other original bulb input line you leave unconnected. (I don’t know what would happen if you connected both of them! So I followed instructions and connected only one). The way I installed my system: It was hard to find locations for the relays and one of the ballasts where the Morimoto instructions said they should go, on the passenger side of the truck. The air box gets in the way a lot. I tried one configuration with the relays next to the radiator, but decided that wouldn’t be a good place because of heat. And I didn’t want to just hang the components with wire ties. I decided to flip the system to the other side of my Sierra. There is plenty of room on the driver’s side, above the tray behind the headlight, and it was just a matter of reversing the instructions for the other side. The Morimoto relays and main part of the harness are designed to be relatively close to the battery, which is on the passenger side. Because I flipped the system from Morimoto’s drawing, I had to add lengths of 12 gauge wire for power and for ground to run power from the battery over to the driver’s side set up (since this is where the relays are now). But it works great and I have good access to all of the components if trouble-shooting or servicing is required, and they are well mounted on the sides of the engine compartment. Criticism (neither of these is a show-stopper): 1. The Morimoto instruction booklet .pdf is clearly written but prints very light. Use a "black and white" setting on your laser printer and high dpi resolution and it comes out a little darker and easier to read. 2. The short extension wire provided in the kit is needed because the Sierra is wider than the average car (this is, after all, a generic set of components that can be make to fit any vehicle). There would be a few more options on where to mount components if the extension wire were a couple of feet longer. The Future: I will keep a spare regular 9012 bulb in my glove box in case the ballasts or relays on the Morimoto kit go T/U. That gives the ability to re-insert an OEM-style bulb in the driver’s side headlight and re-connect the original wire to it, and limp home with at least one headlight, if I have to. (As folks who have worked on Sierra headlights know, the driver's side headlight bulb is easy to reach but the passenger side headlight bulb cannot be reached without removing the air box). Picture: The photo shows, from left to right, the capacitor, the ballast, the relays, and the igniter in the large open space that is above the tray and behind the driver's side headlight. The relays and ballast are pop-riveted to the side of the engine compartment. All of this is on the opposite side from what Morimoto recommends, but I found there was much more room for these components on the driver's side compared to the passenger side. (Since taking the picture, I have secured the capacitor so that it does not move around and hit anything else). On the far right side is the cable run (in the plastic flex tube) that takes the connector wire over to the passenger side ballast and light, as well as carrying the power and ground wires over to their connection points by the battery. I opted for using the plastic flex tube to carry to wires to prevent wire chafing.