[brahmabull]

Hey fellas, this question is for the ones that might know my problem and/or have had similar problems, to see if you guys can diagnose this.

2015 Z/28, I have just passed 1500 miles of a mild break in, and went for a spirited drive in the canyons yesterday. My runs consisted of mostly staying in third gear on a very curvy road, and the Z/28 handled real well(I was following my buddy's 2014 Cayman). Never once lost me, and he was surprised I kept up with him. My problem started when we were done, and was driving around the city. Whenever I accelerate from a complete stop upon taking off from first gear, I would hear a couple of clunks until i reached a much higher speed and or until I switch to second gear. The sound is pretty loud, and I could hear and feel it coming from the rear of the car. I had a passenger in the rear, and she stated she could hear and feel it under the seat. My question is, do you guys think this is the Transmission, Differential or the rear axle. I do remember stopping off at a turnpoint, and had to reverse on a downhill. After reversing, and switching back to first gear and accelerating on an uphill, the "HILL ASSIST" came up on the DIC, and I told myself that's weird. Ever sine then, the clunking sound would happen. I am scheduled to bring it to the dealership first thing in the morning to see what is the culprit, but I just cant fathom to think that after a mild break in that this car that is made to handle some track abuse, would not be able to handle a spirited drive in the canyons. Anybody had this similar thing occur to them with this car or any other car?