If your 2006-2014 Chevrolet Express 2500 Van is experiencing erratic shifting, getting stuck in gear, or throwing transmission codes, the culprit is often a failing Transmission Control Module (TCM). As a workhorse vehicle, any downtime means lost productivity. This T42 TCM, part number 24239926, is the reliable, straightforward solution to get your van back in service without the high costs and delays of a dealership visit.
This isn’t just a part; it’s a complete fix. We pre-program the module to your van’s specific Vehicle Identification Number (VIN) before it ships. This ensures it communicates perfectly with your vehicle’s Powertrain Control Module (PCM) and other systems right out of the box. You can restore crisp, predictable shifting and eliminate frustrating limp mode issues for good.
A Technician’s Notebook: The Misleading P0700 Code
A few months back, a local contractor brought in his ’09 Express 2500. The van was stuck in 3rd gear (limp mode) and the check engine light was on. His scanner just showed a generic P0700 ‘Transmission Control System Malfunction’ code, which can be intimidating. He was worried he needed a full transmission rebuild. After a quick check of the specific transmission codes, we found solenoid circuit faults. In my 20 years of experience, I’ve seen this hundreds of times. The solenoids were fine; the T42 module itself was failing internally, causing the false readings. We swapped in a VIN-programmed module, cleared the codes, and had him back on the road in under an hour. It’s a classic case where replacing the brain, not the muscle, is the right fix.
Is Your Express Van Showing These Red Flags?
- ✔️ Harsh, banging shifts or delayed gear engagement.
- ✔️ Vehicle is stuck in a single gear (often called ‘limp mode’).
- ✔️ Check Engine Light is on with codes like P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔️ The transmission seems to slip between gears or fails to upshift or downshift.
- ✔️ A noticeable decrease in fuel economy due to inefficient shifting.
- ✔️ Complete loss of communication with the transmission module.
Simple Installation to Get Your Van Moving Again
For the Chevy Express and GMC Savana vans, this job is incredibly accessible. No special lifts or tools are needed, making it a perfect repair for a confident DIYer or any professional technician.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the Module: On the 2006-2014 Express/Savana platform, the TCM is conveniently located in the engine compartment on the right-hand (passenger) side.
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs. 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.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s always best practice to use a basic OBD2 scan tool to clear any stored diagnostic trouble codes (DTCs) from the vehicle’s memory.
Verified Fitment for Your GM Vehicle
This module is a direct replacement for part number 24239926 and other interchangeable numbers like 24252114, 24234503, and 24242391. While this page focuses on the 2006-2014 Express 2500 Transmission Module, it also fits a wide range of GM vehicles equipped with 4-speed automatic transmissions (4L60E, 4L65E, 4L70E, 4L80E). Please verify your specific model in the list below:
- Chevrolet Express / GMC Savana 1500, 2500, 3500 (2006-2014)
- Chevrolet Silverado / GMC Sierra 1500, 2500 (2007-2013)
- Chevrolet Tahoe / GMC Yukon (2007-2009)
- Chevrolet Avalanche 1500 (2007-2008)
- Chevrolet Colorado / GMC Canyon (2008-2012)
- Chevrolet Impala (2006-2011)
- Cadillac DTS (2006-2011)
- Hummer H3 (2008-2010)
- …and many more GM cars, trucks, and SUVs.
Frequently Asked Questions
Do I need to take my van to the dealer for programming?
No. This is the biggest benefit. We program the module to your van’s VIN before shipping. It arrives ready for installation, saving you time and the typical dealership programming fee.
What happens if I keep driving with a bad TCM?
Continuing to drive can cause more than just poor performance. It can lead to excessive heat and wear on your transmission’s internal clutches and bands, potentially turning a simple electronics repair into a major mechanical one.
Is this a difficult part to install myself?
For most people with basic hand tools, this is a very manageable job. On the Express Van, the module is easily accessible in the engine bay, and the entire process typically takes less than 30 minutes.
Does this part require a core charge?
No, there is no core charge. You are not required to send your old, faulty module back to us, which simplifies the process for you.
Will this fix a P0700 code?
A P0700 code is a general fault code indicating the TCM has detected a problem. A failing TCM is a very common cause of this code. Replacing it often resolves the P0700 and any related specific transmission codes.