Arrived home after work on Tuesday afternoon to hear a buzsaw sound coming from under the car (2012 78K miles). Took a video of the sound, went in the house to find it's a rather common issue with 2011, 2012 and some 2013 vehicles due to the plastic/nylon race/cage used for the bearings within the 'transmission'. GM replaces them with a metal version under PIP-5081.
I drove right to the dealer that afternoon, within 24 hours my 5 star Chevy dealer calls to tell me the car is repaired and ready to pick up. This was covered under the Voltec 8 yr / 100K warranty (Michigan). He stated if I paid out of pocket, it would have been around $850 to me, much less than most estimates I've seen on this forum an elsewhere online by users.
From the R.O.
1 - 24259842 - BEARING ASM-DRV MOT ROT - Approx $90 retail
1 - 12978390 - Coolant
8 - 8882156 - Fluid (Not sure what this is, maybe to refill the Electric Drive Unit?