Vibration in tailpipe assembly. It makes a growling noise on accelaration or deceleration. I can put pressure on tailpipe and it goes away. Dealer dismisses as water in muffler and “they all have that”
That tells me the exhaust is hitting something it shouldn’t.
Whomever told you this, is an idiot. Don’t speak to them anymore. Talk to someone else at the dealer or take it to another dealer for repair. Any GMC dealer, really any GM dealer, can do warranty repairs on your GMC.
Thanks. I will do what you suggest