Restore Peak Performance to Your Hummer H3 Transmission
If your 2008-2010 Hummer H3 is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, the culprit is often a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GM vehicles, including the rugged H3, sidelined by this issue. This T42 TCM, part number YNXS, is the definitive solution, arriving at your door fully programmed to your vehicle’s VIN. This eliminates the need for expensive dealership visits and gets your truck back on the road—or trail—where it belongs.
The TCM is the brain of your automatic transmission, managing everything from shift points and line pressure to torque converter lockup. When it fails, communication breaks down, leading to the frustrating and potentially damaging symptoms you’re experiencing. Our module restores that critical link, ensuring smooth, predictable shifting and reliable performance. This isn’t just a replacement part; it’s a permanent fix for a common problem.
A Technician’s Notebook
I remember a 2009 Hummer H3 that came into my shop stuck in limp mode (3rd gear only), with the check engine light on and a P0700 code stored. The owner was worried he needed a full transmission rebuild, a multi-thousand-dollar job. After a quick scan confirmed communication issues with the TCM, we ordered a VIN-programmed module. The installation took less than 30 minutes. After reconnecting the battery and clearing the codes, the H3 shifted perfectly on the test drive. The customer saved a fortune and drove away with a reliable vehicle, all thanks to a simple, targeted repair. This is why a quality, pre-programmed 2008-2010 Hummer H3 TCM is one of the best investments you can make.
Is Your Hummer H3 Showing These Telltale Signs?
A failing TCM will give you clear warnings. If you’re noticing any of the following, it’s time to diagnose the module:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction) or various solenoid-related codes (e.g., P0750-P0758).
- ✔ The transmission refuses to upshift or downshift correctly.
- ✔ A noticeable drop in fuel economy or signs of the transmission overheating.
Get Your H3 Back on the Trail: A Simple Installation Guide
One of the best features of this module is its straightforward, plug-and-play installation. No special tools are required, just basic hand tools and about 30 minutes of your time. For the 2008-2010 Hummer H3 TCM, you’ll find it in the engine compartment.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: On the Hummer H3, the TCM is typically located in the right-hand rear of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly to avoid damaging them. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a click as they lock in.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a basic OBD2 scan tool to clear any lingering fault codes from the vehicle’s memory. Your installation is complete.
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct-fit replacement for a wide range of GM vehicles. While this page focuses on the Hummer H3, it is also compatible with the following models. Please verify the location noted for your specific vehicle.
- HUMMER H3 2008-2010 (RH rear engine compartment)
- Chevrolet Colorado 2008-2012 (RH rear engine compartment)
- GMC Canyon 2008-2012 (RH rear engine compartment)
- Chevrolet Silverado & GMC Sierra 1500/2500 2007-2013 (Location varies, often next to battery)
- Chevrolet Tahoe, Suburban, Avalanche & GMC Yukon 2007-2009 (Next to battery)
- Chevrolet Express & GMC Savana Vans 2006-2014 (RH engine compartment)
- And many more Buick, Cadillac, Pontiac, and Saturn models from 2006-2014.
Frequently Asked Questions
Do I need to take my Hummer to the dealer after installation?
No. This module is delivered pre-programmed to your vehicle’s specific VIN. This means it is ready for immediate installation without any additional programming or flashing required from a dealership, saving you time and money.
Where is the TCM located on a 2009 Hummer H3?
On the 2008-2010 Hummer H3, the Transmission Control Module is located in the engine bay, specifically in the right-hand rear corner.
Will this 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 (internal TCM failure) that triggers a P0700, you should always scan for other transmission-specific codes to confirm the diagnosis. In many cases, replacing a faulty TCM will clear this code and its underlying issues.
Is there a core charge for my old part?
No, there is absolutely no core charge. You can keep your old part or dispose of it at your convenience without the hassle of shipping it back.
What does this part interchange with?
This module, YNXS, is a direct replacement for numerous GM part numbers, including 24252114, 24234503, 24242391, 24256960, and many others, ensuring wide compatibility.