raisincane

I found this link through a google search... Can anyone confirm that this is the correct link referred to in original post? http://gm.oemdtc.com/753/vibration-analysis-and-diagnostic-2014-2015-chevrolet-silverado-gmc-sierra

In April of 2015 I traded my 2013 Silverado Z71 crew cab in on a GMC Sierra All Terrain Crew Cab with a standard bed. On my way home from the dealership there was a VERY noticeable vibration from 45-55 miles per hour, and also a vibration at higher speeds(65+). I asked the dealership about the issue and they said the truck may just have flat spots on the tires from sitting on the lot. Told me to drive it a while and see if the problem corrects itself. I didn't argue, however, I could tell and knew that it was in the drivetrain and not in the tires. Upon bringing my truck back for it's first service I brought the vibration issue back up to the dealership and the still blamed the tires. Again, I didn't argue, allowing them to balance, or in my case unbalance all my tires. Apparently, their machine was out of calibration. I was on my way out of town upon completion of service and did not notice they were that far out of balance until I was quite a ways from the dealership. My trip from the dealership was only about two hours to my destination so I continued on and would just take it to a dealership in the area where I was headed. So, after driving for two hours on unbalanced tires and feeling what that feels like there was no question in my mind that my original vibration concern was definitely NOT in the tires. The other dealership re-balanced my tires and didn't address my original vibration concerns. I didn't say anything figuring I'd just get the run around from them too. Anyway, the vibration in the drivetrain was still evident. I talked to my father who has a 2014 Sierra Crew Cab 2WD short box. He said he has the same issue and definitely agreed with me that it is in the drivetrain. About a month and a half ago my dad, a very close family friend, and myself had to run and errand in my truck. The vibration at 50mph was very noticeable that day so, I asked the family friend(retired mechanic and GM mechanic for many, many years). He immediately said it was definitely in the drivetrain and said it felt like a torque issue. Meaning that the drivetrain was creating maximum torque for the gear it was in(overdrive and V4) creating the vibration. He recommended to me shimming the transmission to change the angle of the drive shaft. He said he has had the same vibration issues while building many cars throughout his years and said the shimming was the first place to start. So, I started digging into the issue further and landed here. I read many of the comments here to try and confirm or find a solution. Doesn't seem to be one though. I have yet to try shimming, but am seriously considering trying it after my latest visit to the dealership. While at the dealership for another issue on Thursday I asked the service manager if GM has found a fix for the drivetrain issue and he stated there was nothing that could be done to fix the issue.(FINALLY, A DEALERSHIP ADMITTING THAT THE VIBRATION IS IN THE DRIVETRAIN). He said to me that the issue was with the truck going into V4 creating the vibration. I'm still not satisfied with that answer because I stated to him my 2013 Z71 Crew Cab would go into V4 mode and I didn't experience any vibration issue with that truck. He really didn't have a good answer for that going onto blame the gov't standards set for the issue. Well, I'm hesitant to modifying my truck by shimming it due to possibly voiding my warranty. However, I may just do it anyway and remove the shims prior to taking it in with any future major warranty issues. I love the truck other than the annoying vibration and don't see myself getting rid of it because of that, but as a long time GM truck owner I am disappointed GM would release vehicles with this type of issue being they've been the smoothest riding vehicles on the road for many years. I will let everyone know if the shimming does the trick when I'm able to get to it.