Fix Your GMC’s Shifting Problems for Good
If your 2007-2013 GMC Sierra 1500 is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can bring a tough truck to its knees. This isn’t just an annoyance; it’s a critical failure that affects your truck’s reliability and safety. This OEM-quality T42 Sierra 1500 Transmission Module, part number 24235754, is the definitive solution, arriving pre-programmed to your truck’s VIN for a true plug-and-play repair.
The TCM is the brain of your automatic transmission, controlling everything from shift points to torque converter clutch engagement. When it fails, the symptoms can often be misdiagnosed as internal transmission problems, leading to expensive and unnecessary repairs. By replacing the faulty module, you restore the precise, factory-intended communication between your engine and transmission, bringing back the smooth performance and dependability you expect from your GMC.
From the Diagnostic Bay: The “Bad Solenoid” That Wasn’t
I remember a 2011 Sierra 1500 rolling into my shop. The owner was frustrated, having already spent money at another shop that wanted to drop the transmission pan to replace a shift solenoid based on a generic P0750-range code. The truck was shifting erratically and occasionally going into limp mode. I hooked up my professional scan tool, and while the solenoid code was present, I also saw intermittent communication loss codes (U-codes) that the other shop missed. Experience told me this pointed away from a mechanical part inside the transmission and straight to the electronics controlling it. We ordered a VIN-programmed TCM, installed it in 20 minutes right in the engine bay, and cleared the codes. The truck shifted perfectly on the test drive. The customer saved over a thousand dollars and a lot of downtime by correctly identifying the electronic failure first. That’s the power of a proper diagnosis and the right part.
Is Your Truck Showing These Telltale TCM Failure Signs?
A failing Sierra 1500 Transmission Module can manifest in several ways. If you’re experiencing any of the following, it’s highly likely your TCM is the culprit:
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (often 2nd or 3rd), known as “limp mode.”
- ✔ An illuminated Check Engine Light or Transmission Warning Light.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700 (Transmission Control System Malfunction), U0101, or specific solenoid codes (e.g., P0751, P0756).
- ✔ A sudden drop in fuel economy or the transmission overheating.
- ✔ Complete failure to shift up or down.
DIY-Friendly Installation: Get Your Sierra Shifting Smoothly in Minutes
One of the best features of this module is that it eliminates the need for a trip to the dealership. It comes ready to install right out of the box. For most 2007-2013 Sierra 1500 models, the process is incredibly straightforward.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts and help reset the system.
- Locate the Module: On your Sierra, the TCM is typically located in the engine compartment, mounted right next to the battery.
- Swap the Part: Carefully unplug the electrical connectors from the old module. Unbolt it from its mounting bracket and set it aside. Bolt the new module in its place and securely reconnect the wiring harnesses.
- Final Steps: Reconnect the battery terminal. While the module is pre-programmed, it’s always a good practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory. Start the truck and enjoy your restored transmission performance!
Verified Fitment for Your General Motors Truck or SUV
This T42 TCM is a direct replacement for part number 24235754 and is interchangeable with other service numbers like 24252114, 24234503, and more. While this page focuses on the Sierra 1500 Transmission Module, it also fits a wide range of other GM vehicles. Please verify your part number or use our vehicle lookup tool to ensure perfect compatibility.
Frequently Asked Questions
Frequently Asked Questions
What does a VIN-programmed TCM mean?
It means we flash the module with your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software before we ship it. This ensures it communicates perfectly with your truck’s engine computer and other systems, just like the original part, without needing any expensive dealership tools.