Restore Flawless Shifting to Your HUMMER H3
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 these exact issues. The constant heat and vibration in the engine bay take their toll on sensitive electronics. This T42 TCM, part number 24239926, is the definitive, reliable solution to restore your vehicle’s transmission performance and get you back on and off the road with confidence.
This isn’t just a replacement part; it’s a complete fix. We pre-program the module to your H3’s specific Vehicle Identification Number (VIN) before it ships. This crucial step ensures it communicates flawlessly with your vehicle’s Powertrain Control Module (PCM) and other systems right out of the box. You get to skip the expensive and time-consuming trip to the dealership for programming, making this a straightforward repair for both professional shops and determined DIYers.
Case Study: A Tricky Diagnosis
A customer brought in their 2009 H3 with a complaint of intermittent, harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode), but only after driving for 30+ minutes. The check engine light was on with a general P0700 code. Initial checks of the fluid and solenoids found nothing wrong. After letting the vehicle run in the bay, we were finally able to replicate the issue. The culprit was a heat-soaked TCM that was failing internally once it reached operating temperature. Replacing it with a VIN-programmed module like this one resolved all symptoms instantly. Intermittent electronic failures are common, and a quality part is the only true fix.
Is Your HUMMER H3 Showing These Telltale Signs?
A faulty TCM can manifest in several ways. If you’re experiencing any of the following, it’s a strong indicator that your module needs replacement. Addressing it promptly can prevent further, more costly damage to your transmission’s mechanical components.
- âś” Harsh, slamming shifts or delayed gear engagement.
- âś” Vehicle is stuck in “limp mode” and won’t shift out of 2nd or 3rd gear.
- âś” Check Engine Light or transmission warning light is illuminated.
- âś” Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (e.g., P0751, P0756).
- âś” A complete loss of shifting capability or failure to go into gear.
- âś” Poor acceleration and a noticeable drop in fuel economy.
A Straightforward Guide to Your H3 Installation
Replacing the 2008-2010 HUMMER H3 TCM is a job you can tackle in your own garage in under an hour with basic hand tools. Our VIN programming makes the electronic side of the job completely plug-and-play.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic work.
- Locate the Module: On the HUMMER H3, the TCM is typically found in the engine compartment on the right-hand (passenger) side, towards the rear of the compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs, as they can become brittle over time. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new module securely onto the bracket and plug in the electrical connectors until they click firmly into place.
- Reconnect and Verify: Reconnect the battery terminal. Start the vehicle and check for any warning lights. It’s a good practice to use a basic OBD2 scanner to clear any stored fault codes after the installation is complete.
Verified Fitment for These GM Vehicles
While this is the correct part for the 2008-2010 HUMMER H3, this versatile T42 module also fits a wide range of other General Motors cars, trucks, and SUVs. Please verify your part number (24239926 or an interchange number) for a guaranteed match.
- HUMMER: H3 (2008-2010)
- Chevrolet: Avalanche, Cobalt, Colorado, Express, HHR, Impala, Malibu, Monte Carlo, Silverado, SSR, Suburban, Tahoe
- GMC: Canyon, Envoy, Savana, Sierra, Yukon
- Buick: Allure, LaCrosse, Lucerne, Rainier, Rendezvous
- Cadillac: DTS
- Pontiac: G5, G6, Grand Prix, Pursuit
- Saturn: Aura, Ion, Vue
- Saab: 9-7X
Note: This part interchanges with several numbers, including 24252114, 24234503, 24242391, and others listed in the product data.
Frequently Asked Questions about the HUMMER H3 TCM
Do I need to have this module programmed by a dealer?
No. We handle all the programming for you. Simply provide your vehicle’s VIN at checkout, and the module will arrive ready for immediate installation, saving you hundreds in dealership fees.
What does the Transmission Control Module (TCM) do?
The TCM is the ‘brain’ of your automatic transmission. It receives data from various sensors and controls electronic solenoids inside the transmission to manage shift points, torque converter lockup, and line pressure for smooth and efficient operation.
Is this a difficult part to install myself?
For most individuals with basic mechanical skills, this is a very manageable DIY job. The module is easily accessible in the engine bay, and because it’s pre-programmed, there’s no complex computer work required on your end.
Will replacing the TCM fix my P0700 code?
The P0700 code is a general fault code indicating the TCM has detected a problem. In many cases where the TCM itself is the source of the electrical fault, replacing it will resolve the P0700 code and any related specific codes.
Is there a core charge for this part?
No, there is no core charge. You can keep your old part without the hassle of needing to return it, making the process simpler and more convenient.