Restore Flawless Shifting to Your GM Truck
If your 2007 GMC Sierra 2500 is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re facing a critical failure that compromises your truck’s reliability. The Transmission Control Module (TCM) is the brain of your automatic transmission, and when it fails, it can bring your workhorse to a halt. This T42 TCM, part number 24240400, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN. This means you can skip the expensive trip to the dealership for programming; it’s a true plug-and-play fix that gets you back on the road with confidence.
As the central command for your 4L80E or other compatible GM 4-speed automatic, this module precisely manages shift points, torque converter lockup, and line pressure. A faulty original unit can lead to cascading problems, from poor fuel economy to damaging internal transmission components. By replacing it with this quality-tested unit, you’re not just fixing the symptoms—you’re restoring the original performance and preventing further costly repairs. This is the ideal repair for any DIY mechanic or professional shop looking for a dependable, no-hassle solution for a 2007 Sierra 2500 TCM failure.
Case Study: A Tricky Diagnosis
I remember a 2007 Sierra 2500 HD that came into my shop with a frustratingly intermittent problem. The owner said it would occasionally slam into gear, but by the time he got to me, it would be shifting fine. He’d get a generic P0700 code, but nothing specific. We checked the fluid, wiring, and solenoids—all looked good. After data-logging a drive, we saw the TCM command erratic line pressures just before a harsh shift. It was a classic case of internal TCM failure that doesn’t always throw a specific code. We installed a VIN-programmed T42 module, and the truck has been shifting perfectly ever since. It’s a reminder that sometimes the ‘brain’ is the source of the ghost in the machine.
Is Your Sierra Exhibiting These Telltale Signs?
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ Vehicle is stuck in “limp mode” and won’t shift out of 2nd or 3rd gear.
- ✔ The Check Engine Light or Transmission Warning Light is on, with Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults.
- ✔ Inability to upshift or downshift, leading to poor acceleration and terrible gas mileage.
- ✔ Unpredictable electrical behavior or a complete loss of communication with the transmission.
A Straightforward Guide to Installation
Installing your new 2007 Sierra 2500 TCM is a simple process that most DIYers can complete in under 30 minutes. For this specific truck, the module is typically located in the engine bay, right next to the battery.
- Safety First: Always disconnect the negative terminal from your truck’s battery to prevent electrical shorts and help reset the system.
- Locate the Module: Find the TCM mounted near the battery. It will have several large electrical connectors attached to it.
- Disconnect and Remove: Carefully unclip the wiring harnesses. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new, pre-programmed module in place, securely tightening the bolts. Reconnect the wiring harnesses, ensuring they click firmly into place.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic scan tool to clear any stored fault codes from the vehicle’s memory. Start the engine and test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This module is a direct replacement for part number 24240400 and interchanges with several other service numbers, including 24252114, 24234503, and 24240449. While this page focuses on the 2007 Sierra 2500 TCM, it also fits a wide range of GM vehicles from 2006-2014. Please verify your specific model in the list below:
Partial Fitment List:
- GMC Sierra 2500 Pickup (2007): New style (smooth door skin), 6.0L, located next to the battery.
- Chevrolet Silverado 2500 Pickup (2007): New style (smooth door skin), 6.0L, located next to the battery.
- GMC/Chevrolet Savana/Express Vans (2006-2014): Located in the RH engine compartment.
- Chevrolet Tahoe / GMC Yukon (2007-2009): Located next to the battery.
- Hummer H3 (2008-2010): Located in the RH rear engine compartment.
- Chevrolet Colorado / GMC Canyon (2008-2012): Located in the RH rear engine compartment.
- …and many other GM cars, trucks, and SUVs.
Frequently Asked Questions
Do I need to take my truck to the dealership after installation?
No. This Transmission Control Module comes fully programmed to your vehicle’s VIN. It is a true plug-and-play solution, requiring no additional programming or dealer visits, saving you time and money.
What does ‘No Core Charge’ mean?
It means you do not have to send your old, faulty module back to us. You can keep it or dispose of it yourself, simplifying the entire process.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. While a failing TCM is a very common cause, this code can also be triggered by other transmission issues. If the TCM is the root cause, this part will resolve the code once installed and old codes are cleared.
How do I provide my VIN for programming?
You will be prompted to enter your vehicle’s 17-digit VIN during the checkout process. We need this to load the correct software for your specific vehicle configuration.
Is this part difficult to install for a DIYer?
Not at all. For the Sierra 2500, the TCM is easily accessible in the engine bay. With basic hand tools and our step-by-step guide, most people can complete the replacement in under 30 minutes.