Restore Peak Transmission Performance to Your Hummer H3
Is your 2008, 2009, or 2010 Hummer H3 suffering from frustrating and unpredictable transmission behavior? A faulty Transmission Control Module (TCM) is one of the most common culprits behind issues like harsh shifting, getting stuck in gear, or an illuminated Check Engine Light. As the electronic brain of your automatic transmission, the TCM dictates every shift, and when it fails, it can sideline your vehicle. This T42 TCM, part number 24255280, is the definitive solution, arriving expertly programmed to your vehicle’s specific VIN for a true plug-and-play repair.
Case Study: A Tricky Diagnosis
I recently had a 2009 Hummer H3 in the shop that was giving its owner fits. The complaint was intermittent—sometimes it would slam into gear, other times it would refuse to shift out of 2nd. The owner had already replaced a shift solenoid with no luck. After connecting my scan tool, I saw a generic P0700 code but also a history of intermittent communication loss codes with the TCM. Instead of chasing electrical gremlins for hours, we opted to replace the module. Because our units come pre-programmed, the swap took less than 30 minutes. The result? The H3 shifted like it just rolled off the factory floor. It’s a perfect example of how this single part can resolve a complex-seeming problem without expensive diagnostic guesswork.
Is Your Hummer H3 Exhibiting These Transmission Faults?
A failing TCM doesn’t heal itself; it only gets worse. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement. Addressing it now can prevent further damage to your transmission’s mechanical components.
- ✔ Abrupt, hard, or erratic gear shifts.
- ✔ The vehicle enters “limp mode,” often getting stuck in 2nd or 3rd gear.
- ✔ Check Engine Light or Transmission Warning Light is on, with Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Complete failure to upshift or downshift, leading to poor acceleration.
- ✔ A noticeable drop in fuel economy or signs of the transmission overheating.
Your 30-Minute Path to a Smooth-Shifting H3
For the Hummer H3, this is a straightforward DIY job that requires only basic hand tools, saving you a costly trip to the dealership or repair shop. Our VIN programming means no extra steps are needed after installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement.
- Locate the TCM: On the 2008-2010 Hummer H3, you’ll find the Transmission Control Module in the engine compartment, mounted on the right-hand (passenger side) rear area.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. 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. Ensure they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and allow it to run for a few minutes. While not always necessary, using a basic OBD-II scanner to clear any stored fault codes is good practice. Take a test drive to confirm the smooth shifting performance.
Verified Vehicle Compatibility
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E and 4L65E. While this listing is for 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 / GMC Canyon: 2008-2012 (RH rear engine compartment)
- Chevrolet Silverado / GMC Sierra 1500: 2007-2013 (Next to battery)
- Chevrolet Tahoe / GMC Yukon: 2007-2009 (Next to battery)
- Chevrolet Trailblazer / GMC Envoy: 2006-2009 (LH engine compartment)
- Chevrolet Impala: 2006-2011 (Lower air cleaner housing)
- Cadillac DTS: 2006-2011 (RH front engine compartment)
- And many more GM models from 2006-2014.
Frequently Asked Questions
Do I need to take this part to a dealer for programming?
No. This is the biggest benefit we offer. We program the module to your vehicle’s VIN before shipping it. It arrives ready for immediate installation, saving you time and the high cost of dealership programming.
What is a T42 TCM?
The T42 is the specific hardware platform used by General Motors for the Transmission Control Module in a wide range of vehicles from the mid-2000s to the mid-2010s. It’s the brain that controls the 4L60E, 4L65E, and similar 4-speed automatic transmissions.
Is this part number 24255280 interchangeable with others?
Yes. This module replaces numerous GM service numbers, including 24252114, 24234503, 24242391, and many others listed in the product data. Our programmed module covers all these variations.
What if my problem isn’t fixed?
While this module resolves the vast majority of common transmission electronic faults, we back our parts with a one-year warranty and expert support. If the issue persists, it may indicate a mechanical problem within the transmission itself (e.g., a worn clutch pack or faulty solenoid) that should be diagnosed by a professional mechanic.
Is there a core charge?
No. You are not required to send your old, faulty module back to us. This simplifies the process and gets your vehicle repaired faster.