I am a proud owner of a GMC Yukon 2016 Denali. Since these cars are not officially available in Europe, I imported a Yukon. Basically, I am very satisfied with the vehicle.
But unfortunately, I have a problem with the vehicle, and nobody could help me so far: The car vibrates quite heavily and uncomfortably. The vibrations started when I stopped at the side of the road to let my wife get out. The engine lamp flashed, and the vehicle had hardly any power left. I drove about 1/4 mile, stopped again, and switched off the car. Afterward, I waited for over one minute and then restarted the car. The engine light stayed off, and so I was able to drive on. Also, the power was as usual again. But from there on I had vibrations which I didn't have before.
So I went to a service station to read out any errors and get some help. But there were no errors detected. Since the vibrations did not disappear on the next miles, I went to the dealer again. They reprogrammed the ECU unit with the latest software and balanced the tires. Nothing has changed. So I went to another dealer, hoping that it could help me in a better way. They told me that my tires were worn out and that they could cause the vibrations. We changed all four tires. The handling was a bit better afterward, but the vibrations remained.
Because in my country there are just about 10 GMC Yukon and a few Escalades driving around, no dealer has a clue and can solve my problem. Therefore I did a lot of research on the internet and on the paid platform of GM (ACDelco TDS) - unfortunately without success so far.
I am also familiar with the service bulletins for the 8-speed automatic transmission. But I can exclude these vibrations so far. I have some of these vibrations in my car. However, I have now imported the right oil from Texas by ship, and I will do the oil change within the next days.
But the other vibrations are noticeable at any speed, even at only 1 or 2 mph or over 100 mph. Especially when I ride uphill or downhill, it vibrates a lot. As if I had no suspension in the back and the vehicle would bounce around. The vibrations are mainly felt in the seat. Very slightly also in the steering wheel. From the beginning, my car tends to steer slightly to the left. But I never paid much attention to this, because measuring the track showed that everything is ok.
I am aware that a remote diagnosis is challenging. But perhaps you have any ideas where I should proceed with my further diagnosis? Is the suspension the right start, the drive shaft, or the wheel mounting? Or could it be the engine mounting? Or something completely different? What is the best way to proceed?