If your 2008-2010 HUMMER H3 is suffering from frustrating transmission issues like harsh gear changes, getting stuck in limp mode, or an illuminated check engine light, a failing Transmission Control Module (TCM) is the most likely cause. As the electronic brain of your automatic transmission, the T42 TCM is responsible for every shift. When it fails, it can sideline your rugged H3. This OEM-quality replacement module, part number 24239224, is the definitive solution to restore your vehicle’s performance and reliability.
From the Diagnostic Bay: The Intermittent H3 Shifting Nightmare
A customer brought in a 2009 Hummer H3 with a complaint that stumped a few other shops. The truck would occasionally slam into gear, but other times it drove perfectly. There were no consistent codes, just a history P0700 (Transmission Control System Malfunction). After checking the fluid and wiring harness, everything seemed fine. From experience, I know these T42 modules can fail internally, causing erratic behavior that doesn’t always throw a specific solenoid code immediately. We installed one of our VIN-programmed TCMs, and the problem was solved instantly. The intermittent electrical faults inside the old module were causing the erratic pressure commands, a common failure I’ve seen on hundreds of these GM platforms.
Is Your Hummer H3 Showing These Transmission Red Flags?
A faulty TCM can manifest in several ways. If you’re experiencing any of the following, it’s time to consider a replacement:
- ✔ Harsh, delayed, or erratic shifting between gears.
- ✔ The vehicle is stuck in a single gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is on with codes like P0700, P0750, or other solenoid-related DTCs.
- ✔ Failure to upshift or downshift, leading to poor acceleration.
- ✔ A noticeable decrease in fuel economy.
- ✔ Complete loss of communication with the transmission module.
The Power of Pre-Programmed, Plug-and-Play Simplicity
The biggest hurdle in replacing a modern vehicle module is the programming. We eliminate that step entirely. By providing your vehicle’s VIN at checkout, we program this 2008-2010 HUMMER H3 TCM with the latest GM software specific to your truck. This ensures it works seamlessly right out of the box, with no need for an expensive trip to the dealership or a high-end scan tool for setup. It’s a direct fix that restores shift points, torque converter lockup, and communication for long-term reliability.
Straightforward Installation: Get Your H3 Back in Action
- ✔ 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 2008-2010 Hummer H3, the TCM is located in the engine compartment, on the right-hand (passenger) side towards the rear.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs, as they can become brittle over time. Then, unbolt the old module from its mounting bracket.
- ✔ Install the New TCM: Mount the new module in place and securely fasten it. Reconnect the electrical connectors, ensuring they click into place.
- ✔ Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD2 scanner to clear any stored diagnostic trouble codes (DTCs) from the vehicle’s memory. Start the vehicle and test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number 24239224 and interchanges with many other GM service numbers. While it fits a wide range of GM vehicles, it is guaranteed to fit the following models (please verify your specific location as noted):
- 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 SILVERADO & GMC SIERRA 1500/2500/3500 series (Various years, typically next to battery or on RH side of engine bay)
- CHEVROLET TAHOE, SUBURBAN, AVALANCHE & GMC YUKON (Various years, typically next to battery)
- CADILLAC DTS, BUICK LUCERNE, CHEVROLET IMPALA and many more GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
Why do I need to provide my VIN?
Your Hummer’s VIN allows us to load the exact factory software and calibrations for its specific transmission, engine, and options. This makes the module truly plug-and-play and ensures optimal performance without requiring dealer programming.
Is this a difficult part to install myself?
Not at all. For the Hummer H3, the TCM is easily accessible in the engine bay. With basic hand tools, the swap typically takes less than 30 minutes, making it a perfect job for a DIY mechanic looking to save on labor costs.
Do I need to return my old TCM?
No, there is no core charge for this part. You can keep your old module or dispose of it without the hassle of shipping it back.
Will this fix a P0700 trouble code?
Yes, in many cases. The P0700 code is a general fault code indicating the TCM has detected a problem. If the TCM itself is the source of the fault, replacing it with our programmed module will resolve the issue and allow the code to be cleared.
What is the warranty on this module?
This transmission control module comes with a one-year warranty, giving you peace of mind and confidence in your repair.