If your 2006-2009 Pontiac Montana is starting to feel unpredictable on the road—with harsh, delayed shifts or getting stuck in gear—the problem is often not the transmission itself, but its electronic brain. As a technician with over two decades of experience, I’ve seen countless drivers worry about a costly transmission rebuild when the real culprit was a faulty Transmission Control Module (TCM). This replacement T42 TCM, part number 24239224, is the definitive solution to restore your minivan’s reliability and smooth performance.
The TCM is the nerve center of your automatic transmission. It takes data from sensors all over your vehicle to decide the perfect moment to shift gears. When it starts to fail due to heat cycles and electronic wear, the signals become erratic, leading to the frustrating symptoms you’re likely experiencing. This isn’t just an annoyance; it can be a safety issue when your vehicle doesn’t respond as expected in traffic.
Is Your Montana Showing These Telltale Signs?
A failing TCM will give you clear warnings. In my shop, these are the most common complaints that point directly to a bad module. If you’re noticing any of these, it’s time for a replacement:
- ✔ Harsh, slamming shifts or jerky gear engagement.
- ✔ The vehicle feels stuck in one gear (often called “limp mode”) and won’t upshift or downshift.
- ✔ Your Check Engine Light or a dedicated transmission warning light is on, with Diagnostic Trouble Codes (DTCs) like P0700 (Transmission Control System Malfunction) or various solenoid codes (P0750-P0770).
- ✔ A noticeable drop in fuel economy as the transmission operates inefficiently.
- ✔ Complete loss of communication with the module, preventing the vehicle from starting or shifting out of Park.
A Technician’s Notebook
I recently worked on a 2008 Pontiac Montana that came in with a classic complaint: intermittent, bone-jarring shifts. The owner had already spent money at another shop that couldn’t find the issue because it wouldn’t act up on their test drives. After hooking up my scan tool, I saw communication dropouts from the TCM. These modules, especially on vehicles like the Montana where they are mounted on the LH strut tower, are exposed to constant vibration and heat. This exposure eventually causes internal solder joints to crack, leading to the exact intermittent failures the customer described. We swapped in a VIN-programmed module like this one, and the problem was solved in under 30 minutes. No expensive diagnostic chase, just a straightforward fix.
A Straightforward Guide to Installation
One of the best features of this module is that it arrives programmed to your Montana’s VIN, making installation a simple plug-and-play job you can do at home. No need for a trip to the dealership for expensive programming.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic work.
- Locate the Module: On your 2006-2009 Pontiac Montana, the TCM is typically located on the driver’s side (LH) strut tower in the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly. Then, unbolt the old 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 into place.
- Final Steps: Reconnect the battery terminal. While the module is pre-programmed, it’s always good practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory.
Guaranteed Fitment for Your GM Vehicle
This T42 TCM is a direct replacement for part number 24239224 and is interchangeable with other service numbers. It is designed to fit a wide range of General Motors vehicles. While this page focuses on the 2006-2009 Montana TCM, please verify your model in the list below:
- Pontiac Montana (2006-2009): Transmission; (LH strut tower)
- Buick Allure / LaCrosse (2006-2009): Transmission; (lower air cleaner housing)
- Chevrolet Cobalt (2006-2010): Transmission; (LH strut tower)
- Chevrolet HHR (2006-2011): Transmission; (LH engine compartment)
- Chevrolet Impala (2006-2011): Transmission; (lower air cleaner housing)
- GMC Savana / Chevrolet Express Vans (2006-2014): Transmission; (RH engine compartment)
- GMC Sierra / Chevrolet Silverado Pickups (2007-2013): Transmission; (next to battery)
- …and many more GM models. See the full fitment list provided.
Do I need to have this module programmed by a dealer?
Do I need to have this module programmed by a dealer?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN during checkout, and the module will arrive ready for plug-and-play installation, saving you time and money.
What tools are required for installation?
Installation is simple and typically only requires basic hand tools, such as a socket set and a wrench to disconnect the battery terminal. No specialized electronic tools are needed.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old part or dispose of it without the hassle of returning it, making the process even easier.
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 failing TCM is a very common cause for this code, it’s important to scan for other transmission-specific codes (like P07xx series) to confirm the diagnosis. In most cases, replacing a faulty TCM will resolve the P0700 code.
What is the warranty on this part?
This transmission control module is backed by our one-year warranty, giving you peace of mind and confidence in your repair.