If your Chevrolet Express 2500 work van is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, your Transmission Control Module (TCM) is the likely culprit. As a mechanic with over two decades of experience, I’ve seen how a faulty TCM can bring a reliable workhorse to a dead stop, costing you time and money. This OEM-quality T42 TCM, part number 24239926, is the definitive solution to restore your van’s performance and dependability.
This isn’t just a replacement part; it’s a complete, hassle-free fix. We pre-program the module to your van’s specific Vehicle Identification Number (VIN) before it ships. This critical 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 trip to the dealership for programming, turning a potentially complex repair into a straightforward, driveway-friendly job.
Is Your Express Van Showing These Failure Signs?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s time to diagnose the module. A bad 2006-2014 Express 2500 TCM is often the root cause of these issues:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear), with limited power.
- ✔ An illuminated Check Engine Light or Transmission Warning Light.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid Errors), or other communication codes.
- ✔ Inconsistent upshifting or downshifting, leading to poor acceleration and bad fuel economy.
- ✔ Complete loss of communication with the scan tool or total transmission failure.
From the Diagnostic Bay: The Overlooked Culprit
A customer brought in their ’09 Express 2500, a contractor’s van, complaining of intermittent harsh 1-2 shifts and occasionally getting stuck in 3rd gear after long drives. They’d already replaced two shift solenoids with no luck. The P0700 code kept returning. In these vans, the TCM is mounted on the right-hand side of the engine compartment, where it’s subjected to significant heat. Over years of service, this heat soak degrades the internal circuits. We swapped in a VIN-programmed T42 module, and the problem was solved instantly. It’s a classic failure I’ve diagnosed hundreds of times; the heat kills these modules long before the transmission itself wears out.
A Straightforward 30-Minute Installation Guide
Replacing the 2006-2014 Express 2500 TCM is a job most DIYers or any professional mechanic can handle quickly. No special tools are required.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the onboard systems.
- Locate the Module: On the 2006-2014 Express Van, the TCM is typically located in the engine compartment on the right-hand (passenger) side.
- Disconnect and Remove: Carefully unplug the electrical connectors. 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 battery terminal. While the module is plug-and-play, it’s best practice to use a basic OBD2 scan tool to clear any stored transmission codes to ensure a clean slate for the new module.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24239926 and is interchangeable with many other GM service numbers. While it fits a wide range of vehicles, this listing is specifically for the following:
- ✔ Chevrolet Express 2500 Van: 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014
- ✔ Chevrolet Express 1500 Van: 2006-2014
- ✔ Chevrolet Express 3500 Van: 2006-2014
- ✔ GMC Savana 1500/2500/3500 Van: 2006-2014
This module also fits many other GM cars, trucks, and SUVs including the Silverado, Sierra, Tahoe, Yukon, Impala, and more that use the T42 controller for 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L80E.
Frequently Asked Questions
Do I need to take my van to the dealer after installing this?
No. This module comes pre-programmed to your vehicle’s VIN. This eliminates the need for any additional programming from a dealership or shop, making it a true plug-and-play solution.
What is a T42 TCM?
The T42 is the specific controller generation used by General Motors in the mid-2000s to early 2010s for their 4-speed automatic transmissions. It’s the ‘brain’ that controls all shifting, torque converter lockup, and line pressure.
Will this fix a P0700 code on my 2006-2014 Express 2500 TCM?
A P0700 code is a general fault request from the TCM to the main engine computer. While it can be caused by internal transmission issues, a faulty TCM is a very common cause. Replacing a bad module will often clear this code and the related specific transmission codes.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of returning it.
What information do you need to program the module?
We only need your vehicle’s 17-digit VIN (Vehicle Identification Number) at checkout. We use this to load the correct GM software and calibrations for your specific van.