If your 2006 Chevrolet Trailblazer EXT is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re facing a potential breakdown. As a technician with over two decades of experience, I’ve seen countless GM vehicles sidelined by a faulty Transmission Control Module (TCM). The T42 TCM is the brain of your automatic transmission, and when it fails, it creates chaos. This VIN-programmed T42 TCM, part number 24235732, is the definitive, hassle-free solution to restore your vehicle’s performance and reliability.
Forget about expensive dealership visits and the headache of post-installation programming. We handle the critical step for you. By programming this module to your vehicle’s specific VIN before it ships, we ensure it communicates flawlessly with your engine computer and other systems right out of the box. This is the same process used at the dealership, but delivered directly to you. This module is the key to fixing those frustrating shifting problems and getting your Trailblazer back to driving smoothly and efficiently.
From the Diagnostic Bay
I remember a 2006 Trailblazer EXT that came into my shop with a classic complaint: ‘It shifts hard sometimes, but not always.’ The owner had already replaced a shift solenoid based on a code, but the problem persisted. We hooked up the scanner and saw intermittent communication drops with the TCM. On these GM trucks, the TCM is often mounted in the engine bay where it’s exposed to intense heat cycles. Over time, this heat can cook the internal circuits, causing the exact kind of unpredictable failures he was describing. We installed a VIN-programmed T42 module, and the problem was solved instantly. It’s a textbook example of why replacing the TCM is often the correct fix for persistent, phantom-like shifting issues.
Is Your Trailblazer Exhibiting These Telltale Signs?
- ✔ Unpredictable, harsh, or delayed gear shifts that make driving uncomfortable.
- ✔ The vehicle is stuck in ‘limp mode,’ usually in 2nd or 3rd gear, with limited power.
- ✔ Check Engine Light or Transmission Warning Light is on, with Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0753, or other solenoid-related faults.
- ✔ Complete failure to upshift or downshift, leading to poor acceleration and terrible fuel economy.
- ✔ The transmission seems to slip out of gear or fails to engage properly from Park.
- ✔ Intermittent loss of communication with the module, causing bizarre electrical symptoms.
Straightforward 30-Minute Installation Guide
You don’t need to be a master mechanic to install this part. The process is simple and can be done in your driveway with basic hand tools.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the onboard systems.
- Locate the Old TCM: On the 2006 Trailblazer EXT, the TCM is typically found in the engine compartment on the driver’s side (LH engine compartment).
- Disconnect and Remove: Carefully unplug the wiring harness connectors. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed TCM in place of the old one and securely fasten the bolts. Reconnect the wiring harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD2 scan tool to clear any stored historical fault codes from the system. Start the engine and enjoy smooth shifting!
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct-fit replacement for a wide range of GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page is focused on the 2006 Trailblazer EXT TCM, it is also compatible with the following models. Please verify the location noted for your specific vehicle.
Interchangeable Part Numbers: 24235732, 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24255280, 24256960, 24240449, YNXS.
…fits TRAILBLAZER EXT 06 (LH engine compartment, 8 cylinder), ENVOY 06-09, SAVANA 1500/2500/3500 06-14, SIERRA & SILVERADO 1500/2500 07-13, TAHOE/YUKON 07-09, IMPALA 06-11, HHR 06-11, COBALT 06-10, and many more.
Frequently Asked Questions
Do I need to take my vehicle to the dealer after installation?
No. This module comes fully programmed to your vehicle’s VIN. It is a true plug-and-play solution, saving you the time and expense of a dealership visit for programming.
What is a ‘core charge’ and is there one?
A core charge is a deposit you pay until you return your old part. We do not require a core charge for this TCM, so you can keep your old part without any hassle.
Will this fix a P0700 transmission code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause (the faulty TCM itself), you should ensure any underlying mechanical issues or bad solenoids have also been addressed.
Is this part difficult to install myself?
Not at all. For most DIYers with basic tools, this is a job that takes less than 30 minutes. The module is easily accessible in the engine bay on most compatible vehicles.
What information do you need to program the module?
We only need your vehicle’s 17-digit Vehicle Identification Number (VIN) to program the module with the latest GM software for your specific vehicle configuration.