If you’re dealing with the headaches of a failing transmission in your 2006 Chevrolet Trailblazer EXT, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen countless GM vehicles plagued by erratic shifting, getting stuck in gear, or throwing transmission codes. The culprit is often a faulty Transmission Control Module (TCM). This T42 TCM, part number 24234274, is the definitive, reliable solution to restore your vehicle’s performance and peace of mind.
This isn’t just a replacement part; it’s a complete fix. We pre-program each module to your vehicle’s specific VIN before it ships. This means no expensive trips to the dealership for programming—it’s a true plug-and-play solution. By installing this module, you’re directly addressing the electronic brain of your automatic transmission, ensuring precise gear changes, correct torque converter lockup, and improved fuel economy. It’s the same repair I’d perform in my own service bay.
Case Study: A Tricky Diagnosis
A customer brought in a 2008 Silverado with a classic complaint: “Sometimes it just won’t shift out of 2nd gear.” The check engine light was on, but the codes were intermittent solenoid faults. After checking the wiring harness and solenoids, which tested fine, my experience pointed straight to the TCM. These T42 modules can develop internal fractures from heat and vibration, leading to these ghost-in-the-machine problems. We swapped in a VIN-programmed module, and the truck has been shifting perfectly ever since. This simple replacement saved the customer from a potential transmission rebuild.
Is Your Trailblazer Exhibiting These Telltale Signs?
A failing 2006 Trailblazer EXT TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your module needs replacement:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is illuminated with codes like P0700, P0750, P0755, or other solenoid-related DTCs.
- ✔ Inability to upshift or downshift correctly.
- ✔ A noticeable drop in fuel efficiency.
- ✔ The transmission feels like it’s slipping between gears.
A Straightforward Guide to Installation
One of the best features of this module is its ease of installation. Most DIYers with basic tools can complete the job in under 30 minutes. Your 2006 Trailblazer EXT TCM is located in the engine compartment, on the left-hand side.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the Module: Find the TCM in the engine bay. It’s a small metal box with electrical connectors. On your Trailblazer, it’s typically on the LH side of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical harness connectors. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the wiring harnesses. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a scan tool to clear any stored fault codes from the vehicle’s memory.
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct replacement for part number 24234274 and is compatible with a wide range of GM vehicles equipped with 4-speed automatic transmissions (like the 4L60E, 4L65E, and 4L70E). It also interchanges with part numbers 24252114, 24234503, 24230461, and more. Please verify your specific model below:
- Chevrolet Trailblazer EXT (8 cylinder): 2006 (LH engine compartment)
- Chevrolet Silverado, Tahoe, Suburban, Avalanche: 2007-2013 (Varies, typically next to battery)
- GMC Sierra, Yukon, Envoy: 2006-2013 (Varies, typically next to battery or LH engine compartment)
- Cadillac, Buick, Pontiac, Saturn, Hummer, Saab Models: 2006-2014 (Check specific model for location)
Frequently Asked Questions
Frequently Asked Questions
Do I need to have this TCM programmed by a dealer?
No. We pre-program the module to your vehicle’s VIN before shipping. It arrives ready for plug-and-play installation, saving you time and money.