Restore Your Envoy’s Smooth Shifting and Reliability
If you’re dealing with the frustration of a GMC Envoy that’s shifting erratically, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can bring an otherwise dependable vehicle to a standstill. The T42 TCM, part number 24256960, is the electronic brain of your automatic transmission. It precisely controls shift points, torque converter clutch engagement, and line pressure. When it fails, the symptoms can range from annoying to debilitating, but the solution is straightforward.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We handle the most critical step for you: VIN programming. By programming the module to your specific vehicle’s VIN before it ships, we eliminate the need for expensive dealership tools or programming fees. This ensures that the module communicates flawlessly with your vehicle’s other systems, like the Engine Control Module (ECM), right out of the box. It’s the most efficient way to get your 2006-2009 Envoy back on the road with the performance you expect.
A Technician’s Notebook
I remember a 2008 Envoy that came into my shop. The owner was frustrated because it was stuck in ‘limp mode’—third gear only. He’d already replaced a couple of shift solenoids based on some generic advice, but the problem persisted. A quick scan showed a P0700 (Transmission Control System Malfunction) code, a classic indicator. Instead of throwing more parts at it, we traced the issue to the TCM itself. The internal circuits had failed due to heat and vibration over the years. We installed a VIN-programmed T42 module, cleared the codes, and the Envoy was shifting perfectly within 30 minutes. This part saved the customer hundreds compared to a dealership repair and solved the problem correctly the first time.
Is Your Envoy Exhibiting These Telltale TCM Failure Signs?
A faulty 2006-2009 Envoy TCM can manifest in several ways. If you’re experiencing any of the following, a failing module is the likely culprit:
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear (limp mode).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related codes are present.
- ✔ Failure to upshift or downshift correctly.
- ✔ A noticeable drop in fuel economy.
- ✔ Complete loss of communication with the transmission module.
A Straightforward Guide to Your Envoy TCM Installation
For the confident DIYer or professional mechanic, installing this module is a simple process that requires basic hand tools and can be completed in under an hour. For the 2006-2009 GMC Envoy, the TCM is conveniently located in the engine compartment.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s electronic systems.
- Locate the Module: On the Envoy, you’ll typically find the TCM mounted in the left-hand (driver’s side) of the engine compartment. It’s a silver box with several large electrical connectors.
- Disconnect and Remove: Carefully unclip and remove the electrical connectors. Be gentle with the locking tabs. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the electrical connectors, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. Start the vehicle and allow it to idle for a few minutes. While our programming resolves most issues, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the previous failure.
Verified Compatibility for Your GM Vehicle
While this is the correct part for the 2006-2009 GMC Envoy, this T42 TCM is also a direct-fit replacement for a wide array of other General Motors cars, trucks, and SUVs. It is interchangeable with part numbers 24252114, 24234503, 24230461, 24234274, and others. Please see the detailed list below to confirm your specific model.
Frequently Asked Questions About the 2006-2009 Envoy TCM
What does ‘VIN Programmed’ mean for me?
It means this module arrives ready for installation. We load your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This ensures it works perfectly with your Envoy’s engine and transmission without requiring a trip to the dealership for expensive programming.
Do I need to send my old TCM back (core charge)?
No, there is no core charge for this part. You can keep your old module or dispose of it, making the process hassle-free.
Can I install this myself if I have basic mechanical skills?
Absolutely. The installation is very straightforward, typically involving only a few bolts and electrical connectors. Following our step-by-step guide, most people can complete the job in under 30 minutes with basic tools.
Will this fix a P0700 trouble code?
A P0700 code is a general code indicating the TCM has detected a fault. While a failing TCM is a very common cause, this code can also be triggered by other issues. However, if you are also experiencing symptoms like erratic shifting or limp mode, replacing the TCM is the most probable solution.
What is the warranty on this part?
This transmission control module comes with a one-year, unlimited mileage warranty, giving you peace of mind and confidence in your repair.
Where is the TCM located on my 2007 GMC Envoy?
On the 2006-2009 GMC Envoy, the transmission control module is located in the engine bay, on the driver’s side (LH side).