If your 2008-2010 Hummer H3 is suffering from unpredictable shifting, getting stuck in gear, or has the check engine light on, you’re likely dealing with a failed Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty TCM can sideline even the most rugged vehicles. This isn’t just an annoyance; it’s a critical failure that compromises your H3’s performance and reliability on and off the road. This T42 series TCM, part number 24252114, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
Is Your Hummer H3 Showing These Transmission Red Flags?
A failing TCM sends out clear distress signals. Ignoring them can lead to more severe and costly transmission damage. In my shop, these are the most common symptoms I diagnose that point directly to a bad TCM. If you’re experiencing any of these, it’s time for a replacement.
- ✔ Harsh, slamming shifts or erratic gear changes that feel unpredictable.
- ✔ The vehicle is stuck in “limp mode,” often refusing to shift out of 2nd or 3rd gear.
- ✔ Check Engine Light or Transmission Warning Light is illuminated 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 and terrible fuel mileage.
- ✔ Intermittent loss of communication with the module, causing sporadic issues that are hard to pin down.
Case Study: The Ghost in the Machine
A customer brought in their 2009 Hummer H3 with a frustrating problem. The transmission would work perfectly for days, then suddenly start shifting hard and throw a P0700 code. They had already replaced two shift solenoids at another shop with no success. After hooking up my scan tool and monitoring live data, I noticed the TCM would intermittently drop communication. The root cause wasn’t the solenoids at all; it was the TCM’s internal processor failing under heat. We installed one of our VIN-programmed modules, and the problem was solved permanently. This is a classic example of how a failing 2008-2010 Hummer H3 TCM can mimic other mechanical faults.
Get Your H3 Back on the Trail: A Simple Installation Guide
One of the best features of this module is that you don’t need to be a master mechanic to install it. The entire process can be done in your driveway in under 30 minutes with basic hand tools. Since we program it to your VIN, you can skip the expensive trip to the dealership for programming.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the TCM: On the 2008-2010 Hummer H3, the Transmission Control Module is located in the engine bay, on the right-hand (passenger) side, at the rear of the compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Press the release tabs firmly to avoid breaking 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 negative battery terminal. Start the vehicle and let it idle for a few minutes. While the module is plug-and-play, it’s always a good practice to use a basic scan tool to clear any stored historical fault codes from the system.
Verified Compatibility for Your Vehicle
This module is a direct replacement for part number 24252114 and other interchangeable service numbers. While this page is focused on the 2008-2010 Hummer H3 TCM, this part also fits a wide range of other GM vehicles. Please verify your model and options below.
This part will fit these makes and models with these options
HUMMER H3 08-10 Transmission; (RH rear engine compartment)
ALLURE 06-09 Transmission; (lower air cleaner housing)
AURA 07-09 Transmission; (LH frame rail front)
AVALANCHE 1500 07-08 Transmission; (next to battery)
CANYON 08-12 Transmission; (RH rear engine compartment)
COBALT 06-10 Transmission; (LH strut tower)
COLORADO 08-12 Transmission; (RH rear engine compartment)
DTS 06-11 Transmission; (RH front engine compartment)
ENVOY 06-09 Transmission; (LH engine compartment)
EXPRESS VANS 06-14 Transmission; (RH engine compartment)
G5 07-10 Transmission; (LH strut tower)
G6 06-10 Transmission; (LH strut tower)
GRAND PRIX 06-08 Transmission; (lower air cleaner housing)
HHR 06-11 Transmission; (LH engine compartment)
IMPALA 06-11 Transmission; (lower air cleaner housing)
ION 06-07 Transmission; (behind LH strut tower)
LACROSSE 06-09 Transmission; (lower air cleaner housing)
LUCERNE 06-11 Transmission; (LH engine compartment)
MALIBU 06-10 Transmission; (LH frame rail)
MONTE CARLO 06-07 Transmission; (lower air cleaner housing)
MONTANA 06-09 Transmission; (LH strut tower)
SAAB 9-7X 06-09 Transmission; (LH engine compartment)
SIERRA & SILVERADO TRUCKS 07-13 Transmission; (next to battery)
SUBURBAN 1500 07-08 Transmission; (next to battery)
TAHOE 07-09 Transmission; (next to battery)
TRAILBLAZER 06-09 Transmission; (LH engine compartment)
UPLANDER 06-09 Transmission; (LH strut tower)
VUE 07-10 Transmission; (engine compartment)
YUKON & YUKON XL 07-09 Transmission; (next to battery)
Frequently Asked Questions
Do I need to get this module programmed by a dealer?
No. We pre-program the module to your vehicle’s VIN before shipping. It arrives ready for immediate installation, saving you time and money.
What is a core charge? Do I need to send my old part back?
There is no core charge for this part. You can keep your old module, so there’s no need to worry about return shipping or waiting for a refund.
Is this a reliable, long-term fix?
Absolutely. This module is built to meet or exceed OEM specifications to correct common failure points. It’s backed by our one-year warranty for your peace of mind.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer. While a faulty TCM is a very common cause, this code can also be triggered by other transmission issues. However, if you have P0700 along with other symptoms like erratic shifting or solenoid codes, replacing the TCM is the most likely solution.
What tools do I need for installation?
You’ll typically only need a basic socket set to remove the mounting bolts and a flathead screwdriver to help with the connector tabs if they are stubborn. No specialized tools are required.