2008 Impala SS Traction Control Issue?

I have a 2008 Chevy Impala SS that I have had at the stealership 3 times in the last month. The issue started as a growling noise (not griding noise) in the left front end when backing out of a parking space at a low speed. I assumed that a CV joint was going out, so I took it in, and asked that the front end be checked out and specifically the CV on left front. Called me back to pick up that evening with no work performed becuase no issue found (odd huh, they usually charge for something). The issue was only occuring sporatically so we could not get it to repeat itself for example. Drove the car a few more weeks and the issue started occuring now when turning forward slowly into a left/right direction. Took it back to stealership, and no issue found, no codes, even tho it did occur when they drove it.
Now - still growling when slowing turning forward or reverse, but now the Traction Control light will briefly flash and there is a brief loss of power (There is no engine power message coming up on display). Yesterday was the first time that the issue occured going straight forward - pulled into an auto car wash, washed the car, and went to pull out, but (no growl) the traction light come on, lost all power and ended up pulling tranny down to 1st gear just to pull itself out of wash. Drove the rest of the day with no issue. Dealer is telling me that they do not want to throw parts at it (BTW, I have a good dealer) and that they cannot fix it until it throws a code.
So is it 1) Throttle Position Sensor 2) Accelerator Position Sensor 3) Throttle Actuator Control 4) Wheel Speed Sensor 5) Torque Converter Clutch circuit 6) Hubs

I am at a loss, and these are all of the suggestions that I have found thru research, but no one has posted back with what fixed the issue.

THANKS!