Restore Flawless Shifting to Your GM Vehicle
Are you experiencing frustrating and unpredictable shifting in your 2006-2009 GMC Envoy? Is your truck or SUV stuck in limp mode, or is the check engine light glaring at you from the dashboard? These are classic symptoms of a failing Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every gear change, managing torque converter lockup, and ensuring smooth, efficient operation. When it fails, it can cause a cascade of problems that mimic serious mechanical failure, leading to costly and incorrect repairs.
This OEM-quality T42 Transmission Control Module, corresponding to part number 24235340 and multiple service numbers, is the definitive solution. It arrives at your door expertly programmed to your vehicle’s specific VIN, eliminating the need for expensive dealership visits for programming. This ensures a true plug-and-play installation, getting you back on the road with the smooth performance you expect from your vehicle.
We recently had a 2008 Chevrolet Silverado in the shop with a severe 1-2 hard shift and intermittent solenoid codes. The owner had already spent a significant amount of money replacing the transmission solenoids, believing it was a mechanical issue, but the problem persisted. A quick diagnostic scan revealed communication faults pointing directly to the TCM. We installed one of our VIN-programmed T42 modules, and in under 30 minutes, the truck was shifting perfectly. It’s a common scenario: the root cause is often the electronic controller, not the internal transmission components.
Common Symptoms of a Failing T42 TCM
- ✔ Harsh or Erratic Shifting: Experiencing sudden, jerky gear changes, or a noticeable delay when the transmission shifts.
- ✔ Stuck in Limp Mode: The vehicle refuses to shift out of a single gear (often 2nd or 3rd) to prevent further damage.
- ✔ Check Engine & Transmission Lights: Illumination of dashboard warning lights, often with Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related codes.
- ✔ Failure to Shift: The transmission may not upshift or downshift correctly, leading to poor acceleration and high RPMs.
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter operation can lead to a noticeable decrease in gas mileage.
- ✔ Complete Transmission Failure: In severe cases, a dead TCM can prevent the transmission from engaging at all.
The Advantage of a Pre-Programmed Envoy Transmission Control Module
Solving transmission issues starts with a reliable part. This module is engineered to meet or exceed original equipment standards, ensuring durability and precise performance. The most significant benefit is our complimentary VIN programming service. We load the latest GM software updates directly onto the module, tailored specifically for your vehicle. This process guarantees seamless communication between the TCM, the Engine Control Module (ECM), and other vehicle systems, restoring optimal shift patterns and fuel efficiency right out of the box. No trips to the dealer, no special tools required.
Simple, Straightforward Installation
Designed for both professional technicians and capable DIY enthusiasts, this TCM can typically be replaced in under 30 minutes. The module is located in the engine compartment, with common locations including the LH strut tower, next to the battery, or under the air cleaner box, depending on your specific model. Simply disconnect the vehicle’s battery, unplug the electrical connectors from the old module, unbolt it, and install the new one in its place. Reconnect everything, and you’re ready to go. There is no core charge, so you can keep or dispose of your old part without any hassle.
Frequently Asked Questions
What is VIN programming and why is it essential?
VIN programming involves loading your vehicle’s unique 17-digit Vehicle Identification Number and the corresponding factory software onto the module. This is critical for modern vehicles as it allows the TCM to communicate correctly with the engine and other onboard computers. Without it, the transmission will not function properly. Our service handles this for you, so the part is ready for immediate installation.
Is this a difficult part to install myself?
For most individuals with basic mechanical skills, this is a very manageable job. It typically involves removing a few bolts and disconnecting electrical harnesses. The key is locating the module on your specific vehicle and ensuring the battery is disconnected before you begin. No specialized programming tools are needed.
Will this module fit vehicles other than the 2006-2009 GMC Envoy?
Yes, absolutely. This T42 TCM is compatible with a wide range of General Motors vehicles from roughly 2006 to 2014 that use 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. This includes popular models like the Chevrolet Silverado, Tahoe, Impala, GMC Sierra, Yukon, and many others. Please refer to the detailed fitment list on this page.
Do I need to return my old TCM? Is there a core charge?
No, there is no core charge associated with this part. You are not required to send your old, faulty module back to us, which simplifies the process and saves you money on return shipping.
What happens if I don’t disconnect the battery before installation?
Disconnecting the battery is a crucial safety step. It prevents the risk of electrical shorts that could damage the new module or other vehicle electronics. It also helps reset the vehicle’s computer systems, allowing them to properly recognize the new TCM upon reconnection.