Restore Crisp, Reliable Shifting to Your Chevrolet Trailblazer
If your 2006-2009 Chevy Trailblazer is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re facing a common failure point: the Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GMT360 platform vehicles like the Trailblazer sidelined by a faulty TCM. The constant heat and vibration in the engine bay eventually take their toll on the delicate electronics inside, leading to the frustrating symptoms you’re likely experiencing.
This isn’t a problem that will fix itself. A failing TCM can lead to poor fuel economy, premature transmission wear, and even leave you stranded. Our replacement T42 TCM, part number 24239926, is the definitive, hassle-free solution. We take the guesswork and dealership expense out of the equation by pre-programming the module to your vehicle’s specific VIN. This means it arrives at your door ready for a true plug-and-play installation, restoring the precise, factory-spec shifting your Trailblazer was designed to have.
Case Study: A Tricky Diagnosis
A customer brought in their ’08 Trailblazer with a classic complaint: it would randomly refuse to shift out of 2nd gear, and the check engine light was on. They’d already been quoted over $2,000 for a transmission inspection by another shop. I pulled the codes and saw a P0700 (Transmission Control System Malfunction) and an intermittent solenoid circuit code. Instead of jumping to the worst-case scenario, I checked the TCM. After confirming power and ground, experience pointed to an internal module failure. We installed one of our VIN-programmed modules, and in less than an hour of total time, the Trailblazer was shifting perfectly. The customer saved a fortune and avoided an unnecessary, invasive repair. This is often an electronic problem, not a major mechanical one.
Is Your Trailblazer Showing These Symptoms?
A bad TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your module is the culprit:
- ✔ Harsh, slamming shifts or erratic gear changes.
- ✔ Vehicle is stuck in “limp mode” (usually 2nd or 3rd gear only).
- ✔ Check Engine Light or transmission warning light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ A sudden drop in fuel efficiency.
- ✔ Complete loss of communication with the transmission module (no-start or no-shift condition).
A Straightforward Guide to Installation
For the 2006-2009 Trailblazer, this is a job most DIYers can handle in their own driveway in under 30 minutes. No specialized tools are required.
- 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 typically found in the left-hand (driver’s side) of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. 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 connectors. Ensure they click into place.
- Final Steps: Reconnect the negative battery terminal. Start the vehicle and allow it to run for a few minutes. While not always necessary, using a basic OBD2 scanner to clear any stored fault codes is a good final practice.
Verified Vehicle Compatibility
This module is a direct-fit replacement for the 2006-2009 Trailblazer TCM. It is also compatible with a wide range of other GM vehicles that use the T42 module and 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is a direct replacement for part numbers including 24239926, 24242391, 24234503, and 24252114.
Do I need to take my vehicle to the dealership for programming?
Do I need to take my vehicle to the dealership for programming?
No. The biggest benefit of our service is that 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.
What information do you need from me to program the module?
We only need your vehicle’s 17-digit Vehicle Identification Number (VIN). You can typically find this on your driver’s side dashboard (visible through the windshield) or on the driver’s side door jamb sticker.
Is this a difficult part to install myself?
Not at all. For the Trailblazer, the TCM is easily accessible in the engine bay. With basic hand tools, most people can complete the swap in under 30 minutes. Just follow our simple installation guide.
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.
What kind of warranty is included?
This module is backed by our one-year, hassle-free warranty, giving you confidence and peace of mind in your repair.