redbudga

Hi all, just wanted to add my info. We purchased a new 2014 Crew Cab Sierra 4x4 Z71 the day before thanksgiving, when GMC offered the 20% off. The truck had 4400 miles on it, the sales manager or someone had been driving it; they said legally the dealership can put up to 5500 miles on a new vehicle and still sell it as new. We purchased it at Heritage GMC in Rome Ga, which is about 40 miles away from an Interstate (I75).Everyone there that I have dealt with, has been super nice. I am not bashing this dealership in any way; but I do agree that GM has a problem, and from what I've learned, they know they have a problem with these trucks. I test drove the truck locally in Rome, and didn't notice a vibration, but I have a 30 mile commute on I75 each way, every day. After the Thanksgiving holiday, when I started back to work, I noticed the vibration on the interstate; took it back to the dealership and they rotated and balanced the tires, said 2 were out of spec. Got back on the interstate the next day, still had the vibration. Took back to the dealership for the 2nd time, they put me in their 2015 demo truck (similar to mine) and said they would call me when they had more info on mine. (The 2015 demo truck had the vibration as well). I got a friend of mine, that purchased a truck almost identical to mine about a month before me, to meet me, and rode down the interstate. Within 1 mile I could tell that his rode a lot smoother than mine; so not all of these trucks have the same issue. That's when I started googling the issue, and found this forum. Spoke to the dealership 2 days later, and they road forced balanced the tires on my truck and the tech said he didn't feel what he was feeling in it before. I spoke to the service manager on the phone (very nice guy) he was straight up with me and said his tech thinks he got it fixed, but the service manager said he honestly thought it was something besides the tires causing the problem. He told me I was more than welcome to keep the demo truck for a while, or come back and get mine and try it. He told me they had a vibration testing machine that was coming from GM in a couple of weeks, because they have another truck like mine with a similar vibration. I told him I would go ahead and come over and pick mine up and see if its better. When I got there, the service manager said he had previously went to a class, along with a lot of service managers from other dealerships. Several in the class said their dealership had 1 or 2 trucks that had a vibration that they couldn't get rid of the vibration. GM told them, if you cant get the vibration out by balancing the tires, you are NOT authorized to do anything else to the truck until you get this vibration tester from GM and let it tell you where the vibration is coming from. This would keep them from throwing misc parts at the truck and possibly not replacing the right part. He also told me that his dealership had a truck with the vibration several months ago, and replaced some parts in the rear end, and that solved the issue. Then they had another truck with the vibration, and they replaced the drive shaft and that solved the issue. GM doesn't want them to replace any more parts without having the vibration testing machine. I told him that I had been following these forums and read him some of the comments from a few of the previous pages. One was about a wider gap between the teeth in some of the differential parts. He said that evidently GM contracted several different companies to cast different parts, and some of the parts were cast wrong, or were cast out of spec. Back on the Interstate this am, and still had a vibration, it was better after the road forced balance, but it was still there. Called the dealership and told him it was still there. He said there were 15 or so dealerships on the waiting list for the vibration tester, and that he was 2nd or 3rd on the list. He said it would probably be the first of January when they would receive it, and they would get me to bring mine back so they could put the tester in it, and see what it told them was causing the issue. This dealership has been very straight forward with me, and seems to really want to fix the issue. I will update once I know more. (Do not let your dealership tell you that they don't know what the issue is and has never heard of it; GM is aware and they need to get one of these testers hooked up to your truck)