End Frustrating Shifting Problems in Your GM Truck
If you’re dealing with a 2007-2013 GMC Sierra 1500 that’s shifting harshly, getting stuck in gear, or throwing transmission codes, the problem is very often the Transmission Control Module (TCM). After more than two decades in the diagnostic bay, I’ve seen countless truck owners worry they need a costly transmission rebuild when the real culprit is this electronic brain. This OEM-quality T42 TCM, part number 24243921, is the reliable, cost-effective solution to restore your truck’s performance and your peace of mind.
The TCM is the nerve center of your automatic transmission, managing everything from shift points and line pressure to torque converter lockup. When it fails, communication breaks down, leading to the unpredictable and often dangerous symptoms you’re experiencing. Our module comes pre-programmed to your truck’s specific VIN, eliminating the need for expensive dealership programming. It’s a true plug-and-play fix designed for both professional technicians and determined DIYers.
Case Study: A Tricky Diagnosis
A customer brought in his ’08 Sierra 1500 with a classic complaint: it would randomly refuse to shift out of 3rd gear, and the check engine light was on. His local shop quoted him for a full transmission overhaul. I scanned it and pulled a P0700 (Transmission Control System Malfunction) and a U0101 (Lost Communication with TCM). Instead of tearing into the transmission, I checked the TCM connections first. Seeing no wiring issues, I recommended replacing the module. With our VIN-programmed TCM, the swap took 20 minutes in his driveway. The codes cleared, the truck shifted perfectly, and he saved over two thousand dollars. It’s a textbook example of why you always check the electronics first.
Is Your Sierra Exhibiting These Telltale Signs?
A failing 2007-2013 Sierra 1500 TCM will make its presence known. Look out for these common indicators:
- ✔ Abrupt, harsh, or delayed gear shifts.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0751, or other solenoid-related faults.
- ✔ Complete failure to upshift or downshift.
- ✔ A noticeable drop in fuel economy.
- ✔ Intermittent loss of communication with the module.
A Straightforward Guide to Installation
Replacing the TCM is a job most people can handle in their own garage in under 30 minutes. For the GMC Sierra, you’ll typically find it located right next to the battery in the engine compartment.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts and help reset the system.
- Locate the Module: Find the TCM, which is a small silver box with electrical connectors, usually mounted next to the battery.
- Disconnect and Remove: Carefully unclip the wiring harnesses. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, pre-programmed module into place and securely reconnect the wiring harnesses. You should hear a ‘click’ as they lock in.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the ECU. Start the vehicle and test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This T42 TCM is a direct-fit replacement for a wide array of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page focuses on the 2007-2013 Sierra 1500 TCM, it also interchanges with part numbers 24252114, 24234503, 24230461, and others, fitting models from Chevrolet, GMC, Buick, Cadillac, Pontiac, and more. Please see the detailed list below to confirm your specific application.
Frequently Asked Questions
Do I need to take my truck to a dealer after installation?
No. This Transmission Control Module is delivered pre-programmed to your vehicle’s VIN. This means it’s ready for installation right out of the box, with no additional dealer flashing or programming required.
Is this a new or used part?
This is an OEM-quality replacement part, built to meet or exceed original factory specifications and backed by a one-year warranty for your protection.
What is a core charge?
A core charge is a deposit that is refunded when you return your old part. We do not require a core charge for this module, so you can keep your old part without any hassle.
Will this fix a P0700 code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause (like internal failure), you should ensure there are no wiring or solenoid issues. In the vast majority of cases I’ve diagnosed, a faulty TCM is the direct cause.
Where is the TCM located on my 2011 Sierra 1500?
On most 2007-2013 Sierra and Silverado 1500 models, the TCM is conveniently located in the engine bay, mounted in a bracket directly next to the battery.