Restore Peak Performance to Your GM Transmission
If your 2006 Trailblazer EXT is suffering from erratic shifting, 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 firsthand how a failing Transmission Control Module (TCM) can sideline an otherwise reliable vehicle. This T42 TCM, part number 24240400, is the definitive solution, arriving at your door pre-programmed to your vehicle’s specific VIN. This eliminates the need for expensive dealership programming, turning a complex repair into a straightforward, plug-and-play job you can do at home.
The TCM is the brain of your automatic transmission, managing everything from shift points and line pressure to torque converter lockup. When it fails, the symptoms can range from annoying to dangerous. This module is engineered to meet or exceed original GM specifications, ensuring it restores the crisp, predictable shifting you expect from your truck or SUV. Whether you’re a professional mechanic looking for a reliable part for a customer’s vehicle or a DIYer tackling a weekend project, this module provides a dependable and cost-effective fix for your 2006 Trailblazer EXT Transmission Control Module and many other GM models.
Case Study: The Silverado Stuck in Third Gear
A customer brought in his 2008 Silverado with a classic complaint: the truck felt sluggish and wouldn’t shift past 3rd gear—a textbook case of “limp mode.” The check engine light was on, and a quick scan pulled code P0700 (Transmission Control System Malfunction). After verifying power and ground at the TCM connector, it was clear the module itself had failed internally, a common issue I’ve diagnosed on hundreds of these GM trucks. Instead of a multi-day wait and a hefty bill from the dealer for a new module and programming, we installed one of our VIN-programmed T42 TCMs. The entire job took less than 25 minutes. After a quick battery disconnect to clear memory, the truck was shifting perfectly, and the customer was back on the road the same day for a fraction of the dealership cost.
Is Your Vehicle Exhibiting These Telltale Signs?
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (limp mode), often 2nd or 3rd.
- ✔ An illuminated Check Engine Light or Transmission Warning Light.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750-P0758 (solenoid circuit faults), or U0101 (Lost Communication with TCM).
- ✔ Failure to upshift or downshift, resulting in poor acceleration and terrible fuel mileage.
- ✔ Intermittent loss of communication with the scan tool or other modules.
A Straightforward Guide to Installation
Replacing your 2006 Trailblazer EXT Transmission Control Module is a simple process that typically takes less than 30 minutes. The location varies by model, but it’s generally easy to access in the engine bay.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the Old Module: On your Trailblazer EXT, the TCM is typically found in the left-hand (driver’s side) of the engine compartment. On other GM models, it might be next to the battery, under the air cleaner box, or on the RH side of the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that may need to be gently pried up. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock.
- Final Steps: Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. It’s a good practice to use a basic scan tool to clear any stored fault codes, though the primary issues will be resolved by the new part.
Verified Fitment For These GM Models
This T42 TCM is a direct replacement for a wide array of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is interchangeable with part numbers 24252114, 24234503, 24240400, and others. Please verify your specific model and year from the list below.
This part will fit these makes and models with these options
ENVOY 08-09 Transmission; (LH engine compartment)
SAVANA 3500 VAN 06-14 Transmission; (RH engine compartment)
VUE 07-08 Transmission; 2.4L, (LH front engine compartment)
G5 07-10 Transmission; (LH strut tower)
SIERRA 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
LUCERNE 06-07 Transmission; (4.6L), (LH engine compartment)
VUE 09 Transmission; 2.4L, w/hybrid, LH side front engine compartment, (shift control)
TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
TAHOE 08-09 Transmission; (next to battery), w/o auxiliary oil cooler pump
YUKON XL 1500 07-08 Transmission; (next to battery)
AURA 07-09 Transmission; (LH frame rail front)
RENDEZVOUS 06-07 Transmission; (air cleaner box)
SAAB 9-7X 06-09 Transmission; (LH engine compartment)
SAVANA 2500 VAN 06-14 Transmission; (RH engine compartment)
ALLURE 06-09 Transmission; (lower air cleaner housing)
IMPALA 06-11 Transmission; (lower air cleaner housing)
SILVERADO 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
AND MANY MORE…
Frequently Asked Questions
Frequently Asked Questions
What does “VIN Programmed” mean for me?
It means this module is a true plug-and-play solution. We flash it with the latest GM software calibrated specifically to your vehicle’s Vehicle Identification Number (VIN). This ensures it communicates correctly with your engine and other systems, eliminating the need for a trip to the dealership for expensive programming.
Do I need any special tools for this installation?
No special tools are required. Basic hand tools, such as a socket set to remove the mounting bolts and a small flathead screwdriver to help with the connector tabs, are all you should need. The entire process is designed to be simple for a DIY mechanic.
Will this fix a P0700 trouble code?
In many cases, yes. A P0700 code is a general fault request from the TCM to the main computer to turn on the check engine light. If the TCM itself is the source of the problem, replacing it with our pre-programmed unit will resolve the underlying issue and allow this code to be cleared.
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 needing to send it back to us, simplifying your repair process.
How can I be sure this is the correct part for my vehicle?
The best way is to match the part number from your existing module to the numbers listed here, including 24240400. You can also use our vehicle fitment list or contact our expert support team with your VIN, and we will guarantee you receive the correct part.