Restore Smooth Shifting to Your 2006 Trailblazer EXT
If your 2006 Chevrolet Trailblazer EXT is suffering from harsh shifting, getting stuck in gear, or throwing transmission-related trouble codes, the culprit is often a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty T42 TCM can cripple an otherwise reliable GM vehicle. This isn’t just an annoyance; it’s a critical failure that affects vehicle safety and drivability. This module, part number 24234503, is the brain of your automatic transmission, controlling everything from shift points to torque converter lockup. A failure here leads to the frustrating symptoms you’re likely experiencing.
We solve this problem by providing a high-quality replacement T42 TCM that comes fully programmed to your vehicle’s specific VIN. This means you can skip the expensive trip to the dealership for programming. It arrives ready for a straightforward, plug-and-play installation, making it a perfect solution for both professional mechanics and DIY enthusiasts looking to save time and money. By replacing your old module, you’re not just fixing a part; you’re restoring the precise, factory-designed performance of your Trailblazer’s 4L60E or 4L65E transmission.
A Technician’s Notebook: The Trailblazer Stuck in Limp Mode
A customer brought in their ’06 Trailblazer EXT, complaining it wouldn’t shift past 3rd gear and the check engine light was on. It was a classic case of “limp mode.” My scan tool pulled a P0700 (Transmission Control System Malfunction) and a few solenoid circuit codes. In my shop, I’ve diagnosed hundreds of these T42 TCM failures. Heat cycles and vibrations eventually cause internal solder joints to crack, leading to intermittent or total loss of communication. We installed one of our VIN-programmed modules, cleared the codes, and the vehicle was shifting perfectly on the test drive 30 minutes later. The customer saved hundreds compared to the dealership quote and was back on the road the same day.
Is Your Trailblazer Exhibiting These Telltale Signs?
A failing 2006 Trailblazer EXT Transmission Control Module often announces itself with clear symptoms. If you’re noticing any of the following, it’s a strong indicator that your TCM needs attention:
- ✔ Harsh, delayed, or erratic gear changes that make driving unpleasant.
- ✔ The vehicle is stuck in a single gear (often 2nd or 3rd) and won’t upshift or downshift.
- ✔ Check Engine Light or Transmission Warning Light is illuminated on your dash.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-P0758 (solenoid codes), or communication errors.
- ✔ A noticeable drop in fuel economy as the transmission operates inefficiently.
- ✔ The transmission feels like it’s slipping or failing to engage properly.
DIY-Friendly Installation: Get Your SUV Shifting Smoothly in Minutes
One of the best features of this part is how simple the installation is. You don’t need a vehicle lift or specialized tools. For the 2006 Trailblazer EXT with an 8-cylinder engine, the TCM is conveniently located in the engine compartment. Follow these steps for a successful swap:
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Module: Open the hood and find the TCM. On your Trailblazer, it’s typically mounted on the driver’s side (LH) of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical 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, VIN-programmed TCM into place and securely reconnect the electrical harnesses. Ensure they click into place.
- Final Steps: Reconnect the negative battery terminal. While the system may reset, it’s best practice to use a basic OBD-II scan tool to clear any stored transmission codes. Start the vehicle and take it for a test drive to confirm smooth shifting.
Verified Compatibility for Your GM Vehicle
While this page focuses on the 2006 Trailblazer EXT Transmission Control Module, this T42 TCM is compatible with a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. Please verify your specific model and options below. This part is a direct replacement for service numbers including 24234503, 24252114, and 24242391.
- TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
- CHEVROLET SILVERADO & GMC SIERRA (07-13) Transmission; (next to battery)
- CHEVROLET TAHOE & GMC YUKON (07-09) Transmission; (next to battery)
- CHEVROLET AVALANCHE (07-08) Transmission; (next to battery)
- GMC ENVOY (06-09) Transmission; (LH engine compartment)
- HUMMER H3 (08-10) Transmission; (RH rear engine compartment)
- CHEVROLET EXPRESS & GMC SAVANA VANS (06-14) Transmission; (RH engine compartment)
- …and many other GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
Do I need to take my car to the dealer after installing this TCM?
No. This Transmission Control Module is pre-programmed to your vehicle’s VIN before it ships. This makes it a true plug-and-play solution, eliminating the need for any additional, costly dealership programming.
What tools do I need for installation?
Installation typically only requires basic hand tools, such as a socket set or wrench to remove the mounting bolts and disconnect the battery. No special diagnostic equipment is needed for the installation itself.
Is there a core charge for my old part?
No, there is no core charge. You are not required to send your old, faulty module back to us, which simplifies the process for you.
How do I know this will fix my transmission problem?
This part is designed to fix issues directly caused by a failing TCM, such as the symptoms listed above (erratic shifting, limp mode, specific DTCs). If your vehicle’s issues are due to internal mechanical failure within the transmission (like worn clutches), this part will not resolve them. Proper diagnosis is key.
What if I order the wrong part?
We encourage you to verify fitment using your vehicle’s year, make, and model, or by matching the part number (24234503). If you’re unsure, our expert support team is here to help you confirm compatibility before you order to ensure you get the right part the first time.