Restore Your Transmission’s Performance and Reliability
If your 2006 Trailblazer EXT is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, the problem is often a faulty Transmission Control Module (TCM). As a technician with over 20 years of experience, I’ve seen firsthand how a failing TCM can mimic a major transmission failure, leading to stress and costly misdiagnoses. This T42 series TCM is the definitive solution, pre-programmed to your vehicle’s specific VIN to ensure a seamless, plug-and-play repair that gets you back on the road with confidence.
The TCM is the electronic brain of your automatic transmission, responsible for executing precise gear changes, managing torque converter clutch lockup, and monitoring system health. When it fails, communication breaks down, resulting in the drivability issues you’re experiencing. Our replacement module restores these critical functions, ensuring smooth operation, proper fuel economy, and the longevity of your transmission.
Case Study: A Tricky Diagnosis
A customer brought in a 2006 Trailblazer EXT with classic ‘bad transmission’ symptoms: harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode). They had already been quoted over $2,500 for a transmission rebuild at another shop. After connecting my scan tool, I saw a generic P0700 code and a specific solenoid circuit code. Instead of condemning the transmission, I checked the TCM connectors for corrosion—they were clean. Knowing these T42 modules are a common point of failure, we swapped in a VIN-programmed unit. The total repair time was under an hour, and it completely resolved all shifting issues, saving the customer thousands. This is a perfect example of how the right part can be a simple, effective fix.
Is Your Trailblazer Exhibiting These Transmission Issues?
A failing TCM can manifest in several ways. If you’re noticing any of the following, this module is the likely solution for your 2006 Trailblazer EXT TCM problem.
- ✔ Harsh, jerky, 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) are present, such as P0700, P0750, or other solenoid-related faults.
- ✔ Inconsistent or complete loss of upshifting or downshifting.
- ✔ A noticeable decrease in fuel efficiency.
- ✔ Intermittent communication loss with the transmission.
A Straightforward Guide to Installation
One of the best features of this module is its simple installation. You don’t need to be a professional mechanic to get this job done in your own driveway in under 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s electronic systems.
- Locate the Module: On your 2006 Trailblazer EXT, the TCM is typically found in the engine compartment on the left-hand (driver’s) side.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the electrical connectors, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD2 scanner to clear any stored fault codes from the vehicle’s memory. Start the vehicle and enjoy restored shifting performance.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a direct replacement for part number 24239926 and other interchangeable numbers. It fits a wide range of General Motors vehicles. While this page focuses on the 2006 Trailblazer EXT TCM, please confirm your model is on the list below for guaranteed fitment.
Fits: TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder), and many other GM models including Chevrolet Silverado, Tahoe, Impala; GMC Sierra, Yukon; Buick LaCrosse; Cadillac DTS; Pontiac G6; Saturn Vue, and more. Please verify your specific model and year in our full compatibility chart.
Frequently Asked Questions
Frequently Asked Questions
What does ‘VIN Programmed’ mean?
It means we flash the module with your vehicle’s unique Vehicle Identification Number (VIN) and the latest GM software before shipping. This ensures it communicates perfectly with your vehicle’s other computers right out of the box, eliminating the need for an expensive trip to the dealership for programming.
Do I need any special tools for this installation?
No special tools are required. Basic hand tools like a socket set to remove the mounting bolts and potentially a small flathead screwdriver to help release the connector tabs are all you should need.
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 repair process for you.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. While this module often resolves the underlying issue causing the P0700, you should scan for more specific P-codes (like P0750-P0758) to better pinpoint the fault. A failing TCM is a very common cause.
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 service number on your existing part. If you have any doubts, our expert support team is here to help you confirm compatibility before you order.