Short version: Driving up a 6 percent grade at 35 mph when there's a klunk in the front end and continuing sounds like a plastic bag was caught number the chassis. Stopped to check underneath for nada. Drove to the dealer. All this was fourteen days ago. Solution: GM is putting a new transmission in. 12,000 miles of stress-free driving (although I do have a Stage 1 upgrade). So it goes.
Long version: you don't want to know.

 

It will be interesting to see the direction this thread goes!

 

Glad this thread went no where. GM coughed up a new transmission and sent me on my way. Only hang up was the amount of time it took the dealer to find room in their transmission bays to do the install. Fingers crossed for the next few thousand miles.

 

Hope that fixes you up....... for way more that the next few thousand.

 

Has the same thing happen to mine (non-SS) the week before Christmas. Noticed mine would "click" when reverse was engaged and didn't do it before...