If your 2006-2009 Pontiac Montana is suffering from erratic shifting, getting stuck in gear, or has an illuminated check engine light, you’re likely dealing with a failed Transmission Control Module (TCM). As a seasoned technician with over two decades of experience, I’ve seen countless GM vans exhibit these exact symptoms. Often, owners fear a costly transmission rebuild when the real culprit is this electronic module. This T42 TCM, part number 24256960, is the definitive solution, arriving pre-programmed to your van’s specific VIN for a true plug-and-play repair.
The TCM is the brain of your automatic transmission, controlling everything from shift points to torque converter clutch engagement. When it fails, communication between the engine and transmission breaks down, leading to the frustrating and sometimes unsafe driving conditions you’re experiencing. Our module restores that crucial link, ensuring your transmission operates precisely as the manufacturer intended.
Case Study: A Tricky Diagnosis
A customer brought in their 2008 Montana, convinced the transmission was shot. It was slamming into gear and wouldn’t shift past 2nd. They’d already gotten a quote for over $2,500 for a transmission overhaul. I hooked up my scan tool and immediately saw a P0700 (Transmission Control System Malfunction) and several solenoid circuit codes. While these can point to internal issues, my experience with these T42 modules told me to check the source. We ordered a VIN-programmed TCM, I installed it in under 20 minutes, cleared the codes, and the van shifted perfectly. The customer saved thousands and drove away with a reliable vehicle. It’s a classic case of a simple electronic failure mimicking a major mechanical one.
Is Your Montana Exhibiting These Transmission Issues?
A failing TCM can manifest in several ways. If you notice any of the following, this module is the likely solution for your 2006-2009 Montana TCM problems:
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ Vehicle is stuck in “limp mode” (usually second or third gear).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ Inability to upshift or downshift properly, leading to poor acceleration.
- ✔ A noticeable decrease in fuel economy.
Simple Steps for a DIY Installation
One of the best features of this module is its straightforward installation. You don’t need a trip to the dealership or expensive specialty tools. For the Pontiac Montana, the TCM is typically found on the driver’s side strut tower.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the Module: Find the old TCM on the LH (driver’s side) strut tower in the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Note the tab locations to avoid damage. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new module in the same location and securely reconnect the electrical harnesses. You’ll hear a click when they are properly seated.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a basic OBD2 scan tool to clear any stored transmission codes. Your van is now ready for a test drive.
Verified Fitment Across GM Models
While this is the correct part for your Pontiac Montana, this T42 TCM is also compatible with a wide range of other General Motors vehicles. It is interchangeable with part numbers 24252114, 24234503, 24230461, and more. Please verify your specific model below:
- MONTANA 06-09 Transmission; (LH strut tower)
- UPLANDER 06-09 Transmission; (LH strut tower)
- TERRAZA 06-07 Transmission; (LH strut tower)
- IMPALA 06-11 Transmission; (lower air cleaner housing)
- MONTE CARLO 06-07 Transmission; (lower air cleaner housing)
- GRAND PRIX 06-08 Transmission; (lower air cleaner housing)
- COBALT 06-10 Transmission; (LH strut tower)
- G6 06-10 Transmission; (LH strut tower)
- HHR 06-11 Transmission; (LH engine compartment)
- SILVERADO & SIERRA 1500/2500 (various years, check specific location)
- TAHOE & YUKON (various years, check specific location)
- …and many other GM cars, trucks, and SUVs.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means we load your vehicle’s unique Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures it communicates perfectly with your van’s other computers right out of the box, eliminating the need for an expensive programming service at a dealership.
Is this a difficult part to install myself?
Not at all. For a 2006-2009 Montana, the TCM is easily accessible on the driver’s side strut tower. With basic hand tools, the swap typically takes less than 30 minutes. Just disconnect the battery, swap the modules, and reconnect.
Will this fix a P0700 code?
A P0700 is a general code indicating the TCM has detected a fault. In many cases where the TCM itself has failed internally, replacing it with this programmed unit will resolve the P0700 and any related solenoid codes.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep or dispose of your old module without any hassle.
What kind of warranty is included?
This module comes with a one-year warranty, giving you peace of mind that you’re installing a quality, reliable part that’s built to last.