Restore Flawless Shifting to Your GM Vehicle
If you’re dealing with the frustration of a GMC Envoy that refuses to shift correctly, goes into limp mode, or throws transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen firsthand how a faulty Transmission Control Module (TCM) can mimic a catastrophic transmission failure, leading to unnecessary and expensive repair quotes. This OEM-quality T42 TCM, part number 24243901, is the definitive solution for a wide range of GM vehicles, designed to restore the crisp, predictable shifting you expect.
The biggest hurdle with replacing electronic modules is often the costly and time-consuming trip to the dealership for programming. We eliminate that step entirely. By providing your vehicle’s VIN during checkout, we program the module with the latest GM software updates specifically for your truck or car. This means it arrives at your door ready for a true plug-and-play installation, getting you back on the road faster and saving you hundreds in dealer fees. This isn’t just a replacement part; it’s a complete, hassle-free repair solution for your 2006-2009 Envoy Transmission Module and many other compatible models.
Case Study: The Envoy That Dodged a Rebuild
A customer brought in a 2008 GMC Envoy, convinced he needed a full transmission rebuild. It was stuck in 3rd gear (limp mode), the check engine light was on, and another shop had quoted him over $3,500. After a quick scan, I saw a classic P0700 code along with several solenoid communication errors. Instead of tearing down the transmission, I checked the TCM. In my shop, I’ve diagnosed hundreds of these T42 module failures where internal circuit board cracks, often from heat cycles and vibration, cause these exact intermittent electrical faults. We installed a VIN-programmed module, and in less than an hour, the Envoy was shifting perfectly. The customer saved thousands, all because the problem was correctly identified as the module, not the transmission itself.
Is Your Vehicle Showing These Symptoms?
- ✔ Harsh, erratic, or delayed gear shifts that make driving unpredictable.
- ✔ Vehicle is stuck in a single gear (often called “limp mode”) and won’t upshift or downshift.
- ✔ Check Engine Light or Transmission Warning Light is illuminated on your dash.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, or other solenoid-specific faults.
- ✔ A noticeable drop in fuel economy or signs of the transmission overheating.
- ✔ Complete loss of communication with the transmission module, preventing diagnostics.
A Straightforward Guide to Installation
Replacing your 2006-2009 Envoy Transmission Module is a job most DIYers can handle in their own driveway in under 30 minutes. The location varies slightly by model, but it’s always accessible in the engine bay.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and to help reset the vehicle’s computer systems.
- Locate the Module: On the GMC Envoy, the TCM is typically found in the left-hand (driver’s side) of the engine compartment. On other GM models, it may be next to the battery, under the air cleaner box, or on the LH strut tower.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that may need to be gently pried up. Once disconnected, 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.
- 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 fault codes from the ECU. Start the vehicle and enjoy smooth shifting!
Verified Vehicle Compatibility
This module is a direct replacement for part number 24243901 and is interchangeable with a wide range of service numbers, including 24252114, 24234503, 24240400, and more. It is designed for GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. Below is a partial list of compatible vehicles. Please verify your part number or contact us with your VIN to ensure perfect fitment.
- GMC Envoy: 2006-2009
- Chevrolet Silverado, Tahoe, Suburban: 2007-2013
- GMC Sierra, Yukon: 2007-2013
- Chevrolet Impala, Cobalt, HHR: 2006-2011
- Pontiac G6, Grand Prix: 2006-2010
- Cadillac DTS: 2006-2011
- Hummer H3: 2008-2010
- Saab 9-7X: 2006-2009
- …and many more GM models from 2006-2014.
Frequently Asked Questions
Why is VIN programming so important?
VIN programming loads your vehicle’s specific software, including shift points, torque converter strategy, and communication protocols. A generic or non-programmed module will not work correctly, causing shifting problems or not working at all. Our service saves you a mandatory trip to the dealer.
Is this a difficult part to install myself?
Not at all. This is one of the easier electronic modules to replace. It’s located in the engine bay and requires only basic hand tools. With our pre-programmed module, it’s a simple plug-and-play process that takes less than 30 minutes for most models.
Do I need to return my old part (core charge)?
No, there is no core charge for this part. You can keep your old module or dispose of it without any hassle or extra cost.
What if this doesn’t fix my problem?
While this module fixes the most common causes of the symptoms listed, we’re here to help. Our team of experts can provide diagnostic support. The part is also backed by a one-year warranty for your peace of mind, ensuring you receive a quality, functional component.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code, meaning the TCM has detected a problem and has requested the Check Engine Light be turned on. Often, a failing TCM is the root cause. Replacing it with our programmed unit will typically clear the P0700 and any related solenoid codes.