Restore Peak Performance to Your Hummer H3 Transmission
Is your 2008-2010 Hummer H3 struggling with erratic shifting, getting stuck in gear, or throwing transmission-related trouble codes? These are classic signs of a failing Transmission Control Module (TCM). As a seasoned technician, I’ve seen countless GM vehicles, including the rugged H3, sidelined by a faulty TCM. This isn’t just an annoyance; it compromises your vehicle’s reliability on and off the road. This OEM-quality T42 TCM, part number YNXS, is the definitive solution. It arrives expertly programmed to your vehicle’s specific VIN, eliminating the need for expensive dealership visits and ensuring a true plug-and-play repair.
From the Diagnostic Bay: The Solenoid Trap
A customer brought in their Hummer H3 with a classic complaint: harsh 1-2 shifts and a P0751 code (Shift Solenoid ‘A’ Performance/Stuck Off). They had already replaced the solenoid twice at another shop, but the problem kept returning. After confirming the solenoid’s wiring and resistance were within spec, I suspected the driver circuit inside the TCM. These T42 modules are known to develop internal faults that mimic solenoid failures. We installed one of our VIN-programmed TCMs, and the issue was resolved instantly. The customer had spent hundreds chasing a part that wasn’t the root cause. This highlights why a proper diagnosis points to the TCM when direct component checks pass.
Is Your Hummer H3 Showing These Telltale Symptoms?
A failing TCM can manifest in several ways, often leading to misdiagnosis. If you’re experiencing any of the following, your TCM is the likely culprit.
- ✔ Harsh, delayed, or unpredictable gear shifts.
- ✔ The vehicle enters “limp mode,” often stuck in 2nd or 3rd gear.
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Solenoid codes), or communication errors.
- ✔ Failure to upshift or downshift, leading to poor acceleration and fuel economy.
- ✔ A feeling of the transmission slipping between gears.
Your Straightforward 30-Minute Installation Guide
One of the best features of this module is its simple installation. For the Hummer H3, you’ll find it in the engine compartment, making access easy for any DIY enthusiast or professional mechanic.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the Module: On your 2008-2010 Hummer H3, the TCM is located in the right-hand rear of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors. Note the tab locations to avoid damage. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Reconnect the electrical connectors securely, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. While our VIN programming handles the critical setup, it’s best practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory. Start the vehicle and test drive to confirm smooth shifting.
Verified Compatibility for Your GM Vehicle
While this is the correct part for the 2008-2010 Hummer H3 TCM, this T42 module also fits a wide range of other General Motors vehicles. Please verify your specific model and year from the list below.
- HUMMER H3 (2008-2010) – Transmission; (RH rear engine compartment)
- Chevrolet Avalanche 1500 (2007-2008)
- Chevrolet Cobalt (2006-2010)
- Chevrolet Colorado (2008-2012)
- Chevrolet Express/GMC Savana Vans (2006-2014)
- Chevrolet HHR (2006-2011)
- Chevrolet Impala (2006-2011)
- Chevrolet Malibu (2006-2010)
- Chevrolet Monte Carlo (2006-2007)
- Chevrolet Silverado/GMC Sierra 1500/2500 (2007-2013) – Non-hybrid
- Chevrolet Suburban/GMC Yukon XL 1500 (2007-2008)
- Chevrolet Tahoe/GMC Yukon (2007-2009) – Non-hybrid
- Buick Allure/LaCrosse (2006-2009)
- Buick Lucerne (2006-2011)
- Cadillac DTS (2006-2011)
- GMC Canyon (2008-2012)
- GMC Envoy/Chevrolet Trailblazer (2006-2009) – 8 cylinder models
- Pontiac G5/G6 (2006-2010)
- Pontiac Grand Prix (2006-2008)
- Saab 9-7X (2006-2009)
- Saturn Aura (2007-2009)
- Saturn Ion (2006-2007)
- Saturn Vue (2007-2010)
Frequently Asked Questions
Do I need to take my Hummer to the dealer after installation?
Do I need to take my Hummer to the dealer after installation?
No. This module is delivered pre-programmed to your vehicle’s VIN. This means it’s ready for installation right out of the box, with no additional programming or flashing required. It’s a true plug-and-play solution.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. A failing TCM is a very common cause of this code. Replacing it with our programmed unit will resolve the P0700, provided the TCM was the root cause of the specific underlying transmission fault.
What is the warranty on this part?
This transmission control module comes with a one-year warranty, giving you peace of mind and confidence in your repair.
Is there a core charge for my old TCM?
No, there is no core charge. You can keep your old part without any hassle or need to ship it back, simplifying the repair process for you.
Is part number YNXS interchangeable with other numbers?
Yes. The YNXS service number is interchangeable with many other GM part numbers for the T42 module, including 24242391, 24234503, and 24252114, among others. Our module is a direct replacement for all compatible service numbers.