Restore Peak Transmission Performance to Your HUMMER H3
If your 2008-2010 HUMMER H3 is suffering from erratic shifting, getting stuck in gear, or has an illuminated check engine light, a faulty Transmission Control Module (TCM) is the most likely culprit. As a seasoned technician with over two decades of experience, I’ve seen firsthand how a failing TCM can sideline even the most rugged vehicles. This T42 TCM, part number 24239926, is the definitive solution, arriving expertly pre-programmed to your vehicle’s specific VIN. This means no expensive trips to the dealership for coding—it’s a true plug-and-play fix that gets you back on the road and trail with confidence.
Case Study: The “Limp Mode” H3
A customer brought in their 2009 H3, stuck in what we call “limp mode”—it wouldn’t shift past 2nd gear. The dash was lit up with a check engine light, and my scan tool pulled a P0700 (Transmission Control System Malfunction) and several solenoid circuit codes. After verifying the wiring harness was intact, all signs pointed to the TCM. These modules are notorious for internal circuit board failures from years of heat cycles. Instead of a costly and time-consuming dealer visit, we installed one of our VIN-programmed T42 modules. The entire job took less than 30 minutes. After a quick battery disconnect and clearing the old codes, the H3 shifted perfectly on the test drive. The customer saved hundreds on programming and labor, and drove away with a reliable vehicle.
Is Your HUMMER H3 Showing These Transmission Warning Signs?
A failing TCM doesn’t get better on its own. Ignoring these symptoms can lead to more significant transmission damage. Here’s what to look for:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in a single gear (limp mode), often 2nd or 3rd.
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, especially P0700, P0750, or other solenoid-related faults.
- ✔ Unpredictable upshifting or downshifting, leading to poor acceleration.
- ✔ A noticeable decrease in fuel economy.
- ✔ Complete loss of communication with the transmission module.
The Advantage of a Pre-Programmed 2008-2010 HUMMER H3 TCM
The biggest hurdle in replacing a modern electronic module is programming. We eliminate that step entirely. By providing your vehicle’s VIN during checkout, we flash the module with the latest, most stable GM software specific to your H3. This ensures perfect communication between the engine and transmission, restoring the precise shift points and torque converter lockup strategy designed by the factory for optimal performance and fuel efficiency.
A Straightforward Guide to Your H3 TCM Installation
You don’t need to be a master mechanic to perform this replacement. With basic hand tools, you can have this job done in your own driveway.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the Module: On the HUMMER H3, the TCM is typically found in the engine compartment on the right-hand (passenger) side, near the rear of the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Note the locking tabs to avoid damage. 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 until they click.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a basic OBD2 scan tool to clear any stored diagnostic trouble codes. Take the vehicle for a test drive to confirm smooth operation.
Frequently Asked Questions
Do I need to take this part to a dealer for programming?
Absolutely not. This module comes fully programmed to your vehicle’s VIN. It is ready for installation right out of the box, saving you time and money.
Will this fix my transmission shifting problems?
If your vehicle’s issues match the symptoms listed (like harsh shifts, limp mode, or specific TCM codes), this part is the most common and effective solution. It directly addresses failures within the transmission’s electronic control system.
Where is the TCM located on my 2008-2010 Hummer H3?
The TCM is located in the engine bay, on the right-hand (passenger) side towards the rear of the engine compartment.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module without any extra fees or hassle.
What kind of warranty comes with this module?
This part is backed by our standard one-year warranty, covering any defects in materials or workmanship for your peace of mind.
Verified Vehicle Compatibility List
This T42 TCM is a direct fit for the 2008-2010 HUMMER H3. It is also compatible with a wide range of other GM vehicles. Please verify your part number (24239926) or contact us with your VIN to ensure perfect fitment. It is interchangeable with the following part numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24240400, 24241806, 24243901, 24243921, 24255280, 24256960, 24235732, 24235753, and 24240449.