Fix Your Trailblazer’s Shifting Problems for Good
If you’re dealing with a 2006 Trailblazer EXT that’s shifting erratically, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen countless GM vehicles, especially SUVs like the Trailblazer, sidelined by a faulty Transmission Control Module (TCM). The symptoms can be frustrating and even unsafe—one minute you’re driving fine, the next your truck is stuck in limp mode. This isn’t just an inconvenience; it’s a critical failure that compromises your vehicle’s performance and reliability.
This T42 TCM, part number 24235753, is the definitive solution. It’s not just a replacement part; it’s a direct-fit, pre-programmed fix that eliminates the guesswork and costly dealership visits. We handle the complex part by programming the module to your vehicle’s specific VIN before it ships. This means when it arrives, it’s ready for a true plug-and-play installation, restoring the precise, smooth shifting you expect from your truck. Don’t let a bad module dictate your driving experience. Get the right part, programmed correctly, and get back on the road with confidence.
Case Study: The Ghost in the Transmission
A customer brought in his ’06 Trailblazer complaining of what he called “transmission ghosts.” It would shift hard into second gear, then suddenly refuse to shift past third. He’d already replaced a shift solenoid based on a code, but the problem persisted intermittently. After connecting my scan tool, I saw the classic P0700 code, which is just a general fault request from the TCM. Digging deeper, I noticed erratic voltage readings from the module itself. The internal processor was failing, causing it to send corrupted commands to perfectly good solenoids. We installed one of our VIN-programmed T42 modules, and the problem vanished instantly. It’s a textbook example of why you must address the root cause—the TCM—to avoid wasting time and money on other parts.
Is Your Trailblazer Showing These Telltale Signs?
A failing TCM doesn’t always mean a complete transmission breakdown. Often, the signs are subtle at first and then worsen over time. If you’re experiencing any of the following, your 2006 Trailblazer EXT TCM is the most likely culprit.
- ✔ Harsh, banging, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults are present.
- ✔ Complete loss of upshifting or downshifting capabilities.
- ✔ A noticeable decrease in fuel economy.
- ✔ The transmission seems to slip out of gear unexpectedly.
A Straightforward Guide to Installation
One of the best parts about this module is that it’s designed for a straightforward DIY installation. You don’t need a lift or specialized transmission tools. For the 2006 Trailblazer EXT with an 8-cylinder engine, the process is simple.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the TCM: On your Trailblazer, the TCM is located in the engine compartment on the left-hand (driver’s) side. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the wiring harnesses. They have locking tabs that need to be pressed. Once disconnected, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, VIN-programmed TCM into place. Securely plug the wiring harnesses back in until they click, ensuring a solid connection.
- Reconnect and Verify: Reconnect the battery terminal. Start the vehicle and let it idle for a minute. It’s a good practice to use a basic OBD2 scan tool to clear any lingering fault codes from the system’s memory. Take a test drive to confirm the smooth shifting performance.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24235753 and is interchangeable with many other GM service numbers, ensuring broad compatibility. While this page focuses on the 2006 Trailblazer EXT TCM, it also fits the following vehicles. Always verify your specific model and 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 & G6 06-10 Transmission; (LH strut tower)
- HUMMER H3 08-10 Transmission; (RH rear engine compartment)
- SAAB 9-7X 06-09 Transmission; (LH engine compartment)
- CADILLAC DTS 06-11 Transmission; (RH front engine compartment)
- And many more GM models from 2006-2014.
Do I need to get this module programmed by a dealer?
Do I need to get this module programmed by a dealer?
No. This is the biggest benefit of our service. We pre-program the module to your vehicle’s VIN before shipping. This makes it a true plug-and-play part, saving you the time, hassle, and expense of a dealership visit.
Is this a new or used part?
This is an OEM-quality replacement part, built to meet or exceed original factory specifications. It is inspected and programmed to ensure reliability and comes with a one-year warranty for your peace of mind.
What tools are required for installation?
Installation typically requires only basic hand tools. A socket set to remove the mounting bolts (commonly 10mm) and a flathead screwdriver to help release the connector tabs are usually all that’s needed. The entire process often takes less than 30 minutes.
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. You can keep it or dispose of it at your convenience, simplifying the repair process for you.