Transmission Control Module not shifting gears. Remains in 2nd gear, won't go over 45 mph. Dealer supposedly replaced the TCM a year ago under the extended warranty, but is acting up again. Took it to another Chevy dealer a year later (Oct 2018) and they said the TCM is "fried" and would cost $1,400 to replace. I don't believe the dealer because it kicked back in for a few minutes and drove fine, but went back out again.

From the forums I've read, the most common cause is a break in the connection to the left front speed control sensor, which I have replaced. But because its connection to the ABS harness won't connect securely due to a broken retainer clip, the TCM is still not functioning. Tried to find the harness at parts stores but they tell me that part (that connects to the speed control sensor) is only available through a dealer.

Dealer told me yesterday that the part costs $121.00, and I said, "Just for a connector?" Parts man said, "Yep." So now I will try to force a solid connection with either velcro wrapped around it or wire the two direct by soldering to bypass the connectors. I'm not really sure that will fix it because it could be a faulty TCM, but I don't know where it is located. That's why I found this website, trying to locate the TCM to check and clean the connections to it. So for now I'm screwed.