I see there is a thread here on this but it's from 2007 and my situation is not exactly the same.

One week ago today, while going up a hill the traction control light came on (the error on the dash, the T/C light) after I stopped at the next traffic light the car began hard shifting, or what it felt like to me is that she was SLAMMING into gear. I got to my destination and let the car sit for about 5 minutes. When I got in again the light was off and I drove around the neighborhood and everything was fine. I was actually waiting for my daughter at her piano lesson so I sat for another 15 minutes or so. Then we left, everything seemed fine and then the T/C light came on again, so did the check engine light and she started slamming into gear again. I had to make one more stop. Car sat for probably an hour. No T/C light but check engine stayed on and wouldn't go off. Took her in to the mechanic the next morning with the engine light still on but the T/C light not on but I did explain all that had happened.

They ran the diagnostics and she threw more codes than they had ever seen (or so they claim) PO011, PO014, PO053,54, PO0116,128,131,133,134, PO135,137,138, PO141, PO326,420,446,454,464,496, PO856, P1V33, PU74, P1400, P1574, PZA00, PZA01

They decided the fix was:
Hard fault code for cam sensor, removed and replaced CAMSHAFT SENSOR $117.06 + labor.

Car seemed fine until today, exactly one week since it happened before. Driving along and the T/C light came on and she started slamming into gear again.

Took her back to the same mechanic. First off the guy tried to convince me that is NOT the traction control light. "It's your tires." Um, no, that IS the traction control light, I'm not an idiot and I can read both the owner's manual and the internet. He's still not convinced that's what that light means. This cannot be good.

He drives the car (I go with him) he says that I have a broken engine mount.

My dad and I both think this guy is insane. If I had a broken engine mount would it stop being a problem for 6 days and then suddenly start up again?? Broken is broken. If it was broken and that "thing" I was feeling was the engine MOVING it wouldn't stop for a week would it???

I really need help here, I think this guy is trying to rip me off.

 

You need a new mechanic.

 

I would guess either the under hood fuse box but usually you get U codes also. Or the TCM (Transmission Control Module). Or you are losing a data line.

You need a new mechanic for sure!!!

This may be something only a dealership tech can diagnose, but there are some good independent techs out there, they are just hard to find.

 

It may need the VVt solenoids, 20 minutes and about $110.00 in parts from Chevy cured my problums, thanks to Whopper.

 

Time to get the codes read again -but use a different mechanic. As ChevyMgr says, it may be a problem with the connections under the fuse box etc - and may need a Chevy tech to diagnose. Post the codes here and we'll see what advice we can offer.

 

Here we go again did your mechanic replace the camshaft sensor or camshaft solenoid. There are two solenoids, The intake and the exhaust solenoid. They are the ones that give you the T/C light and a check engine light with hard trans shift.