If your 2008-2010 Hummer H3 is suffering from jarring shifts, getting stuck in gear, or has an illuminated check engine light, a failing Transmission Control Module (TCM) is the most likely culprit. As the electronic brain of your 4L60E or 4L65E transmission, the TCM dictates every shift, ensuring your H3 performs reliably both on and off-road. This OEM-quality T42 TCM, part number 24240449, is the definitive solution, arriving pre-programmed to your vehicle’s VIN for a true plug-and-play repair.
From the Diagnostic Bay
I recently had a 2009 Hummer H3 come into the shop that had its owner completely stumped. The vehicle would intermittently refuse to shift out of 2nd gear and was throwing a generic P0700 transmission fault code. The owner had already replaced two shift solenoids with no success. After a quick data scan, I saw erratic pressure readings commanded by the TCM. These T42 modules, especially when exposed to years of engine bay heat cycles, can develop internal circuit failures that cause these exact ghost-in-the-machine problems. Installing a VIN-programmed 2008-2010 Hummer H3 TCM resolved all the issues in under an hour, saving the customer from a costly and unnecessary transmission rebuild.
Is Your Hummer H3 Showing These Telltale Signs?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s time to consider a replacement:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ Inability to upshift or downshift, leading to poor acceleration and fuel economy.
- ✔ The transmission feels like it’s slipping between gears.
A Straightforward Installation Guide for Your H3
Replacing the 2008-2010 Hummer H3 TCM is a job most DIYers can handle in their own driveway. 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 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. Press the release tabs firmly. Then, unbolt the old module from its mounting bracket.
- Install the New TCM: Mount the new module in place and securely fasten the bolts. Reconnect the electrical connectors, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. Start the vehicle and use a standard OBD2 scan tool to clear any stored fault codes from the computer’s memory.
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct replacement for part number 24240449 and other service numbers. While this page is focused on the Hummer H3, this module is also compatible with a wide range of GM vehicles. Please verify your part number or consult the list below.
- HUMMER H3 (2008-2010) – Transmission; (RH rear engine compartment)
- Chevrolet Avalanche 1500 (2007-2008)
- Chevrolet Cobalt (2006-2010)
- Chevrolet Colorado (2008-2012)
- Chevrolet Express/GMC Savana Vans (2006-2014)
- Chevrolet HHR (2006-2011)
- Chevrolet Impala (2006-2011)
- Chevrolet Silverado/GMC Sierra 1500/2500 (2007-2013)
- GMC Canyon (2008-2012)
- GMC Envoy (2006-2009)
- Buick LaCrosse/Allure (2006-2009)
- Buick Lucerne (2006-2011)
- Cadillac DTS (2006-2011)
- Pontiac G5/G6 (2006-2010)
- Saturn Aura/Vue/Ion (2006-2010)
- And many more.
Frequently Asked Questions About the 2008-2010 Hummer H3 TCM
Frequently Asked Questions
What does “VIN Programmed” mean for my Hummer?
It means we load your vehicle’s unique Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures it communicates perfectly with your H3’s engine computer and other systems right out of the box, eliminating the need for a dealership visit.
Will this fix my transmission’s hard shifting problem?
Yes, in the vast majority of cases, erratic shifting, delayed engagement, and limp mode in the Hummer H3 are caused by a faulty TCM. This part is designed to be the direct solution for those electronic failures.
Do I need to send my old TCM back (core charge)?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly without any extra hassle or fees.
Where is the TCM located on a 2009 Hummer H3?
The transmission control module on the 2008-2010 Hummer H3 is located in the engine bay, on the passenger side (RH) towards the firewall.
Is this an OEM part?
This is a high-quality replacement part built to meet or exceed original equipment manufacturer (OEM) specifications for performance and reliability, backed by a one-year warranty.