I have a2009GMC2500, last Friday I had to pull the truck out of a slick spot. It wasn't too bad just needed some assistant because it was pulling a trailer. We pulled it backwards about 20ft and the brake light came on. It then acted like it was stuck in gear. I presume 4th after reading online. Got the truck back to the shop and pulled the codes. The only one was U0101 lost communication with the TCM. I tried clearing it out but it keep just coming right back. I then unhooked the batteries and got the code cleared. Took off driving and everything was fine till about 2 miles and then the abs, brake and traction control lights came on and it was back in 4th gear. Checked all the connections at the transmission and TCM and everything was fine. Could the TCM have gone out our do I have other problems? Also can I buy a used TCM and put it in the truck without reprogramming? Thanks