Restore Peak Performance to Your Hummer H3 Transmission
As a technician with two decades of experience under the hood, I’ve seen firsthand how a failing Transmission Control Module (TCM) can sideline even the most rugged vehicles like the Hummer H3. If you’re dealing with frustrating and unpredictable shifting, getting stuck in limp mode on the trail, or seeing that dreaded check engine light, you’re not alone. The TCM is the brain of your automatic transmission, and when it falters, the entire driving experience suffers. This T42 Transmission Control Module, part number 24255280, is the definitive, reliable solution for your 2008-2010 Hummer H3.
The biggest headache with replacing electronic modules is often the expensive and time-consuming trip to the dealership for programming. We eliminate that step entirely. We flash this module with the latest GM software updates and program it directly to your Hummer’s Vehicle Identification Number (VIN) before it ships. This means it arrives at your door ready for a true plug-and-play installation, instantly communicating with your vehicle’s systems to restore crisp, correct shifting and clear persistent fault codes. This isn’t just a replacement part; it’s a permanent fix designed to get your H3 performing dependably again, whether you’re navigating city streets or tackling tough terrain.
A Technician’s Notebook: The Overlooked H3 TCM Failure
I remember a 2009 H3 that came into the shop with a classic intermittent problem. The owner complained of harsh 1-2 shifts and occasionally getting stuck in 3rd gear, but only after driving for 30+ minutes. We couldn’t find any mechanical faults with the 4L60E transmission itself. The issue was heat soak. The TCM on the H3 is located in the right rear of the engine compartment, where it’s exposed to significant heat. Over time, this thermal stress causes internal electronic components to fail intermittently. A simple replacement with a pre-programmed module like this one resolved the issue completely, saving the customer from a costly and unnecessary transmission rebuild.
Is Your Hummer H3 Showing These Symptoms?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement:
- âś” Harsh, erratic, or delayed gear shifts.
- âś” Vehicle is stuck in a single gear (often called “limp mode”).
- âś” Check Engine Light or Transmission Warning Light is illuminated.
- âś” Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-P0758 (solenoid codes), or U0100 (loss of communication).
- âś” Failure to upshift or downshift properly.
- âś” A noticeable decrease in fuel economy.
- âś” The torque converter fails to lock up, leading to higher RPMs at cruising speed.
Why Our Pre-Programmed 2008-2010 Hummer H3 TCM is the Smart Choice
This isn’t just another part. It’s a comprehensive solution built on years of diagnostic experience. It directly addresses the common failure points of the original T42 module, providing a dependable, long-term fix that restores the vehicle’s intended operation and your peace of mind. Backed by a one-year warranty, you can be confident in its quality and performance.
A Straightforward Guide to Installation
For the confident DIYer or professional mechanic, installing this module is a simple job that typically takes less than 30 minutes. No specialized programming tools are required.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s adaptive memory.
- 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 from the old TCM. 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, ensuring they click into place.
- Reconnect and Verify: Reconnect the negative battery terminal. Start the vehicle and check for any warning lights. While not always necessary, using a basic scan tool to clear any stored historical codes is good practice.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number 24255280 and is interchangeable with many other GM service numbers. While it is guaranteed to fit the specified Hummer H3, it also fits a wide range of other GM vehicles, including:
- HUMMER H3: 2008-2010 (RH rear engine compartment)
- Chevrolet Silverado & GMC Sierra 1500/2500: 2007-2013 (Typically next to the battery)
- Chevrolet Tahoe & GMC Yukon: 2007-2009 (Typically next to the battery)
- Chevrolet Colorado & GMC Canyon: 2008-2012 (RH rear engine compartment)
- Chevrolet Express & GMC Savana Vans: 2006-2014 (RH engine compartment)
- Cadillac DTS: 2006-2011 (RH front engine compartment)
- Chevrolet Impala: 2006-2011 (Lower air cleaner housing)
- Pontiac G6: 2006-2010 (LH strut tower)
- …and many other GM models. Please verify your part number or contact us for fitment confirmation.
Do I need to have this module programmed by a dealer?
Do I need to have this module programmed by a dealer?
No. This is the key benefit of our service. We program the module to your vehicle’s specific VIN before shipping. It arrives ready to install, saving you hundreds of dollars and the hassle of a dealership appointment.
Is this a simple plug-and-play installation?
Yes. Once you locate the old TCM on your Hummer H3, you simply unbolt it, unplug the connectors, and install the new one. No special tools or software are needed.
What if my part number is slightly different?
This T42 module is interchangeable with a wide range of part numbers, including 24252114, 24234503, 24242391, and others. As long as your vehicle is on the compatibility list, this module will function correctly. When in doubt, send us your VIN and we’ll verify compatibility for you.
Is there a core charge for my old part?
No, there is no core charge. You are not required to send your old, faulty module back to us, making the process simpler and more convenient for you.
What kind of warranty is included?
We stand behind our products with a one-year, hassle-free warranty. This covers any defects in the module, giving you confidence and peace of mind in your purchase.