If your 2008-2010 Hummer H3 is suffering from erratic shifting, 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 automatic transmission, the TCM is responsible for every gear change, torque converter lockup, and line pressure adjustment. When it fails, it can make your rugged H3 feel unpredictable and unsafe. This OEM-quality T42 TCM, part number 24235732, is the definitive solution, arriving expertly programmed to your vehicle’s specific VIN for a true plug-and-play repair.
A Technician’s Notebook: The Intermittent H3
I had a 2009 Hummer H3 in the bay last month with a problem that was driving the owner crazy. It would shift perfectly for days, then suddenly start banging into gear or refuse to shift out of 2nd. The codes were intermittent—mostly a generic P0700 (Transmission Control System Malfunction). After checking the wiring and solenoids, which all tested fine, experience pointed me to the TCM. These modules are notorious for developing internal electronic faults from heat and vibration. We installed one of our pre-programmed TCMs, and the problem was solved instantly. The customer avoided a costly dealership visit and got his H3 back on the trail the same day. This is the exact fix for that common scenario.
Is Your Hummer H3 Showing These Telltale Signs?
A faulty TCM doesn’t always mean total transmission failure. Often, the signs are subtle at first and worsen over time. If you’re experiencing any of the following, it’s time to diagnose your TCM:
- ✔ Harsh, delayed, or unpredictable gear shifts.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is on with codes like P0700, P0750, or other solenoid-related DTCs.
- ✔ Failure to upshift or downshift, resulting in poor acceleration.
- ✔ A noticeable drop in fuel economy.
- ✔ Inability to communicate with the TCM using a scan tool.
A Straightforward 30-Minute Installation Guide
Replacing the 2008-2010 Hummer H3 TCM is a simple job that most DIYers can handle with basic tools. Because this module comes pre-programmed to your VIN, you can skip the expensive trip to the dealer for programming.
- 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 located in the engine compartment, on the right-hand (passenger) side towards the rear of the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly to avoid breaking them. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new module securely onto the bracket and reconnect the electrical harnesses. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a standard OBD2 scan tool to clear any stored diagnostic trouble codes from the system.
Verified Vehicle Compatibility
This module is a direct-fit replacement for the following vehicles and configurations. While this part is an exact match for the Hummer H3, it is also interchangeable with a wide range of GM vehicles using the T42 TCM.
- ✔ HUMMER H3 2008-2010 (Transmission; RH rear engine compartment)
- ✔ Chevrolet Colorado 2008-2012 (Transmission; RH rear engine compartment)
- ✔ GMC Canyon 2008-2012 (Transmission; RH rear engine compartment)
- ✔ Chevrolet & GMC Vans (Express, Savana 1500/2500/3500) 2006-2014 (Transmission; RH engine compartment)
- ✔ Chevrolet & GMC Trucks (Silverado, Sierra 1500/2500) 2007-2013 (Transmission; next to battery)
- ✔ Chevrolet & GMC SUVs (Tahoe, Yukon, Suburban, Avalanche) 2007-2009 (Transmission; next to battery)
- ✔ And many other GM cars, trucks, and SUVs from 2006-2014. Please verify your part number.
Frequently Asked Questions
How does the VIN programming work?
During checkout, you provide your vehicle’s 17-digit VIN. We then flash the module with the latest GM-certified software specific to your vehicle’s configuration. This ensures it works perfectly right out of the box, with no additional programming needed.
Do I need any special tools for installation?
No special tools are required. Basic hand tools like a socket set and ratchet are all you need to unbolt the old module and install the new one. A standard OBD2 scanner is recommended to clear codes after installation.
Is there a core charge for my old part?
No, there is absolutely no core charge. You can keep your old module or dispose of it at your convenience, making the process hassle-free.
Will this fix a P0700 code on my Hummer H3?
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, a failing TCM is the root cause. Replacing the module with our programmed unit is a very common and effective solution for this and related transmission codes.