Fix Your Truck’s Shifting Problems for Good
If you’re behind the wheel of a 2007 GMC Sierra 2500 HD, you count on its power and reliability. But when the transmission starts acting up—slamming into gear, refusing to shift, or throwing a check engine light—it can be incredibly frustrating and concerning. In my 20+ years as a technician, I’ve seen countless drivers worry they need a full transmission rebuild when the real culprit is a faulty Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, and when it fails, the entire system’s performance suffers. This T42 series module, part number 24235754, is the definitive solution to restore your truck’s crisp, predictable shifting.
We take the guesswork and dealership hassle out of the equation. Unlike a generic part off the shelf, this module arrives at your door pre-programmed to your truck’s specific Vehicle Identification Number (VIN). This means no expensive trips to the dealer for programming. It’s a true plug-and-play fix designed for both professional mechanics and determined DIYers. By installing this OEM-quality 2007 Sierra 2500 Transmission Control Module, you’re not just replacing a part; you’re restoring the precise communication between your engine and transmission, ensuring longevity and peak performance.
From the Diagnostic Bay: The Case of the ‘Dead’ Transmission
I remember a customer bringing in his Sierra 2500, convinced he was facing a $4,000 transmission replacement. The truck was stuck in limp mode (3rd gear only) and shifting was violent when it did engage. He’d been quoted a massive repair bill elsewhere. After pulling the codes, I saw a classic P0700 (Transmission Control System Malfunction) and several solenoid circuit errors. Instead of pulling the pan, I checked the TCM first. After swapping in a VIN-programmed module, every single issue vanished. The truck shifted like new. That 30-minute job saved him thousands and reminded me that proper diagnosis always starts with the brain. A faulty TCM can perfectly mimic a major mechanical failure.
Is Your Sierra Exhibiting These Telltale TCM Failure Signs?
A failing TCM can manifest in various ways. If you’re experiencing any of the following, it’s highly likely your module is the source of the problem. Replacing your 2007 Sierra 2500 Transmission Control Module can resolve these issues.
- âś” Harsh, erratic, or delayed gear shifts that make driving uncomfortable.
- âś” The vehicle gets stuck in one gear, often called “limp mode,” as a protective measure.
- âś” An illuminated Check Engine Light or Transmission Warning Light on your dash.
- âś” Diagnostic Trouble Codes (DTCs) such as P0700, P0750, or other solenoid-related codes are stored.
- âś” A noticeable drop in fuel economy as the transmission isn’t operating efficiently.
- âś” The transmission feels like it’s slipping, where engine RPMs rise but the truck doesn’t accelerate accordingly.
- âś” Complete loss of communication with the module, preventing shifting altogether.
A Straightforward Guide to Installation
You don’t need to be a master mechanic to install this part. For most GMT900 trucks like the Sierra, the TCM is easily accessible in the engine bay, often right next to the battery. The entire process typically takes less than 30 minutes.
- Safety First: Before you begin, disconnect the negative terminal from your truck’s battery to prevent any electrical shorts and help reset the vehicle’s electronic systems.
- Locate the Module: On your 2007 Sierra 2500, the TCM is typically mounted in a bracket next to the battery. It’s a silver box with several large electrical connectors.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that need to be released. Once disconnected, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely plug in the wiring harnesses, ensuring they click to confirm a solid connection.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s always a good practice to use a basic OBD2 scan tool to clear any lingering fault codes from the vehicle’s memory. Start the truck and enjoy smooth shifting!
Guaranteed Fitment for Your GM Vehicle
This T42 Transmission Control Module is a direct replacement for part number 24235754 and is interchangeable with many other service numbers. It is designed for a wide range of GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, 4L70E, and 4L80E. While this page focuses on the 2007 Sierra 2500 Transmission Control Module, please verify your specific model in the list below.
- âś” GMC Sierra 2500 Pickup (2007): New body style (smooth door skin), with 6.0L engine, located next to the battery.
- âś” Chevrolet Silverado 2500 Pickup (2007): New body style (smooth door skin), with 6.0L engine, located next to the battery.
- âś” GMC & Chevrolet Express/Savana Vans (2006-2014): Located in the RH engine compartment.
- âś” Chevrolet Tahoe & GMC Yukon (2007-2009): Located next to the battery.
- âś” …and many other GM cars, trucks, and SUVs from 2006-2014. See the full fitment list for details.
Frequently Asked Questions
Does this TCM require any additional programming?
No. This module is delivered fully programmed to your vehicle’s VIN. It is ready for installation right out of the box, saving you a trip to the dealership and their programming fees.
What is the warranty on this part?
This part comes with a one-year warranty, giving you peace of mind and confidence in your repair. We stand behind the quality and reliability of our electronic components.
Is this a difficult part to install myself?
For most individuals with basic hand tools, this is a very straightforward installation. The module is typically easy to access in the engine bay, and the entire swap can be completed in under 30 minutes.
Will this fix my P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While a faulty TCM is a very common cause, this code can also be triggered by other transmission issues. However, if you’re also experiencing erratic shifting or other symptoms listed here, replacing the TCM is the most likely solution.
Why shouldn’t I just get a used one from a junkyard?
A used TCM from a junkyard will be programmed to the donor vehicle’s VIN and options, causing compatibility issues with your truck. Furthermore, you have no way of knowing its condition or remaining lifespan. Our module is tested, programmed specifically for you, and backed by a warranty.