vibration in a brand new t680

Hi All

I just got a brand new t680. It only had 350 miles on it, we are now up to 2000 miles but from the start there has been a strong and consistent vibration. It is always there but sometimes worse than others. It doesnt seem to matter if its uphill or down, even when it goes to 600rpm coast mode it is vibrating. It seems to be felt worse when standing in the middle of the sleeper floor, but its annoying enough in the drivers seat and passenger seats. You can feel it in the steering wheel. I really cant figure out where to start looking for the problem. I work for a good company but I dont want to seem ungrateful and immediately start complaining after having just been trusted with a brand new truck. Id at least like to have some idea first. Any helpful suggestions on where to start or if anyone else has had an issue with a new t680 that they worked out what was it?

Thanks for all your help