Chevy Customer Service
Join Date: Nov 2010
Location: Detroit, Michigan USA
As the owner, you definitely have the right to repair your vehicle as you see fit, but my best recommendation to hold tight and have a dealership look at it. I understand not wanting to wait until Monday with a vehicle issue. It might be the TCM, it might not, and with them looking at it in person they would be able to make that call. After that diagnosis, you would know for sure and can proceed as you see fit.
Please keep in touch! PM me after you are in with the dealer to let me know how things went.
GM Customer Service