Restore Crisp, Reliable Shifting to Your 2006 Trailblazer EXT
If your 2006 Chevrolet Trailblazer EXT is plagued by unpredictable shifting, getting stuck in gear, or a persistent check engine light, you’re likely dealing with a failed Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen how a faulty TCM can mimic a major transmission failure, causing unnecessary stress and diagnostic headaches. This T42 Transmission Control Module, part number 24255280, is the definitive, hassle-free solution. It arrives expertly programmed to your vehicle’s specific VIN, eliminating the need for expensive dealership visits and ensuring a true plug-and-play installation.
Case Study: A Tricky Diagnosis
A customer brought in a 2006 Trailblazer EXT with a classic complaint: intermittent harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode). They had already replaced two shift solenoids based on DTCs, but the problem persisted. After a quick data scan, I noticed erratic command signals from the TCM. Instead of a costly transmission teardown, we installed one of these pre-programmed T42 modules. In under 30 minutes, the vehicle was shifting perfectly. This case highlights a common scenario: the root cause isn’t mechanical wear, but a failure in the electronic brain—the TCM. This part saved the customer over a thousand dollars in unnecessary repairs.
Is Your Trailblazer Exhibiting These Symptoms?
A failing TCM can manifest in various ways, often confusingly. Before you suspect a full transmission rebuild, check if your vehicle is showing these common signs of a faulty 2006 Trailblazer EXT TCM:
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ Vehicle is stuck in a single gear (often called “limp mode”).
- ✔ The check engine light or transmission warning light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid errors), or U-series communication codes.
- ✔ Poor acceleration and decreased fuel economy.
- ✔ Intermittent loss of communication with the module, causing gauges or other electronics to act erratically.
Your 30-Minute Path to Smoother Shifting
One of the biggest advantages of this module is its straightforward installation, which most DIYers can complete with basic hand tools. No complex wiring or dealer-level programming is required. For the 2006 Trailblazer EXT TCM, the location is typically in the engine compartment on the left-hand side.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the Old Module: On your Trailblazer EXT, find the TCM in the LH engine compartment. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical harnesses. Then, unbolt the module from its mounting bracket.
- Install the New Module: Mount the new, pre-programmed TCM in the same location and securely fasten it. Reconnect the electrical harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a few minutes. If you have a basic scan tool, it’s good practice to clear any stored fault codes. Take a test drive to confirm the smooth shifting performance.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number 24255280 and is interchangeable with many other GM service numbers. While this page focuses on the 2006 Trailblazer EXT TCM, it also fits a wide range of other GM vehicles. Please verify your specific model below:
This part will fit these makes and models with these options:
- TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
- ENVOY 06-09 Transmission; (LH engine compartment)
- SAVANA & EXPRESS VANS (1500/2500/3500) 06-14 Transmission; (RH engine compartment)
- SILVERADO & SIERRA 1500/2500 07-13 Transmission; (next to battery)
- TAHOE & YUKON 07-09 Transmission; (next to battery)
- IMPALA 06-11 Transmission; (lower air cleaner housing)
- COBALT & G5 06-10 Transmission; (LH strut tower)
- HUMMER H3 08-10 Transmission; (RH rear engine compartment)
- CADILLAC DTS 06-11 Transmission; (RH front engine compartment)
- …and many more models listed in the original fitment data.
Frequently Asked Questions
Do I need to get this module programmed by a dealer?
No. This module is delivered to you pre-programmed to your vehicle’s VIN. It is ready for installation right out of the box, saving you time and money.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of returning it.
What is the warranty on this TCM?
This transmission control module comes with a one-year warranty, giving you peace of mind and confidence in your repair.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request. While a faulty TCM is a very common cause for this code, you should always diagnose any accompanying specific codes (like for solenoids or sensors). In many cases, replacing the TCM will resolve the P0700 and related issues.
Where is the TCM located on my 2006 Trailblazer EXT?
On the 2006 Trailblazer EXT, the TCM is typically found in the engine compartment on the left-hand (driver’s) side.