MThompsonjr115

I'll join this club... My '14 GMC Sierra SLT AT CCRB 4x4 5.3 with nearly 24k miles vibrates. I bought it at 17k miles, certified pre-owned and never noticed any bad vibrations until my trip to Pittsburgh with my family. With 3 adults in the truck the vibration at 75mph was horrible! Adding a 4th person made the vibration smooth out a touch. Needless to say I did not cruise at 75mph out there and back. In the last 2 weeks it's developed a vibration/binding/moaning noise from the transmission to rear-end area under med-hard acceleration, while rolling or a stand still. The same day I noticed this, it sounded like something in rear-end was grinding while backing up out of a driveway. Dealer can't get me in till the 13th of October... I guess I'll get the run around then. EDIT: The MPG have fallen about 1-2MPG on average since that trip. I usually average around 17.5-18MPG to work and back all week, now I fight to get 16-16.5MPG. Maybe it's related to the issue? Idk.