Restore Peak Transmission Performance to Your Hummer H3
Is your 2008-2010 Hummer H3 suffering from erratic shifting, getting stuck in gear, or displaying a persistent check engine light? These are classic signs of a failing Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every gear change, managing torque converter lockup, and monitoring system health. When it falters, your vehicle’s drivability and reliability are severely compromised. This genuine GM T42 Transmission Control Module, service part number 24240449, is the definitive solution to restore the smooth, predictable performance your H3 was built for.
From the Diagnostic Bay
We had a 2009 Hummer H3 come into the shop that was stuck in what the owner called ‘limp mode.’ It wouldn’t shift out of 3rd gear, and the dash was lit up with transmission warnings. The owner had already spent money replacing a couple of shift solenoids based on a generic code reader’s output, but the problem persisted. After a proper scan, we identified communication errors pointing directly to the TCM. Instead of continuing to chase individual components, we installed a VIN-programmed T42 module. The difference was immediate. All codes cleared, the transmission shifted perfectly through all gears, and the customer was back on the road with a reliable vehicle. It’s a prime example of how addressing the core electronic controller is often the correct, and ultimately more cost-effective, repair.
Diagnosing Your 2008-2010 Hummer H3 TCM Failure
A faulty TCM can manifest in various ways, often mimicking other transmission problems. If you’re experiencing any of the following symptoms, your module is the likely culprit. This replacement part is engineered to resolve these exact issues, providing a lasting solution without the need for additional dealership visits.
- ✔ Erratic Shifting: Experiencing harsh, delayed, or unpredictable gear changes that make driving uncomfortable and unsafe.
- ✔ Stuck in Gear: The vehicle refuses to shift up or down, often getting stuck in a single gear (limp mode) to prevent further damage.
- ✔ Warning Lights: The Check Engine Light or a dedicated transmission warning light is illuminated on your dashboard.
- ✔ Diagnostic Trouble Codes (DTCs): Your mechanic finds codes like P0700 (Transmission Control System Malfunction), P0750, or other solenoid-related faults.
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter operation caused by the failing TCM can lead to a noticeable drop in MPG.
- ✔ No Communication: A scan tool may be unable to communicate with the transmission module, indicating a complete failure.
Plug-and-Play Solution with VIN Programming
The biggest hurdle in replacing modern vehicle electronics is programming. This module eliminates that problem entirely. We pre-program the TCM to your Hummer H3’s specific Vehicle Identification Number (VIN) before it ships. This ensures it arrives ready for immediate installation, loaded with the latest GM software updates for optimal performance. You get a direct-fit, plug-and-play part that communicates flawlessly with your vehicle’s other systems, just like the original factory module.
This T42 module is a direct replacement for a wide range of service numbers, including 24252114, 24234503, 24230461, 24234274, 24240449, and many more, making it a versatile solution for numerous GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E.
Frequently Asked Questions
Does this TCM require programming at the dealership?
No. This module comes pre-programmed to your vehicle’s specific VIN. It is a true plug-and-play solution, saving you the time and expense of a dealership visit for programming.
Where is the TCM located on a 2008-2010 Hummer H3?
On the 2008-2010 Hummer H3, the Transmission Control Module is typically located in the engine compartment, specifically at the right-hand rear side.
Will this part fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause (like internal circuit failure) that triggers a P0700 and other specific codes, you should always perform a full diagnostic scan to confirm the TCM is the point of failure.
Is this a new or used part?
This is a high-quality, OEM-standard replacement part, inspected and programmed to ensure it meets or exceeds original factory specifications for performance and longevity.
Do I need to return my old TCM?
No, there is no core charge for this part. You can keep your old module without any hassle or additional fees.