If you’re experiencing frustrating and unpredictable transmission behavior in your 2006 GMC Envoy XL, you’re not alone. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can turn a reliable SUV into a source of constant worry. Hard slams into gear, getting stuck in limp mode, or a persistent check engine light are classic signs that the brain of your transmission is failing. This T42 TCM, part number 24241806, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
This isn’t just a replacement part; it’s a restoration of your vehicle’s performance and your peace of mind. We load it with the latest GM-certified software, ensuring it communicates flawlessly with your vehicle’s Powertrain Control Module (PCM) and other systems right out of the box. This eliminates the need for expensive dealership programming, saving you time and money. By precisely managing shift points, torque converter clutch engagement, and fluid pressure, this module resolves common issues and helps protect your transmission from further wear and tear. Get your Envoy XL shifting smoothly and reliably again with a part built to meet and exceed original equipment standards.
Case Study: A Tricky Diagnosis
A customer brought in their ’06 Envoy XL with a complaint of intermittent, violent 1-2 shifts and a P0751 (Shift Solenoid ‘A’ Performance/Stuck Off) code that kept returning even after replacing the solenoid. They were about to spend a fortune on a transmission rebuild. In my experience, when a solenoid code won’t clear after replacing the part, the driver circuit in the TCM is often the culprit. We swapped in one of our pre-programmed T42 modules, cleared the codes, and the problem was solved instantly. The customer saved over a thousand dollars by correctly identifying the electronic failure instead of a mechanical one.
Is Your Envoy Exhibiting These Telltale Signs?
A faulty TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your module needs replacement. Ignoring these symptoms can lead to more significant transmission damage.
- ✔ Harsh, erratic, or delayed gear shifting.
- ✔ Vehicle is stuck in a single gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as the general P0700 or specific solenoid codes like P0750, P0751, P0752, etc.
- ✔ Failure to upshift or downshift properly as you accelerate or decelerate.
- ✔ A noticeable decrease in fuel economy.
- ✔ The torque converter fails to lock up at highway speeds, causing higher RPMs.
A Straightforward Guide to Installation
For the confident DIYer, replacing the TCM is a simple job that typically takes less than 30 minutes. No specialized tools are required.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic work.
- Locate the Module: On the 2006 Envoy XL with the 8-cylinder engine, the TCM is found in the left-hand (driver’s side) engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt it from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical connectors. Ensure they click into place.
- Reconnect and Verify: Reconnect the negative battery terminal. Start the vehicle. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the system.
Verified Vehicle Compatibility
This T42 TCM is a direct fit for a wide range of General Motors vehicles. Please confirm your model and the specified location notes below. This part is interchangeable with service numbers such as 24252114, 24234503, 24230461, and 24241806.
- Envoy (8-Cylinder) 2006-2007 (LH engine compartment)
- Envoy XL (8-Cylinder) 2006 (LH engine compartment)
- Trailblazer (8-Cylinder) 2006-2007 (LH engine compartment)
- Chevrolet Silverado 1500 / GMC Sierra 1500 2007-2013 (Next to battery)
- Chevrolet Tahoe / GMC Yukon 2007-2009 (Next to battery)
- Chevrolet Suburban 1500 / Yukon XL 1500 2007-2008 (Next to battery)
- Chevrolet Express / GMC Savana Vans 2006-2014 (RH engine compartment)
- Cadillac DTS 2006-2011 (RH front engine compartment)
- And many more models including Impala, LaCrosse, Grand Prix, HHR, Cobalt, G6, and Saab 9-7X.
Frequently Asked Questions
Does this module really not require a trip to the dealer?
That’s correct. We program the module to your vehicle’s VIN before shipping it. This ensures it works correctly right out of the box, with no need for additional programming or calibration fees.
What is a TCM and what does it do?
The Transmission Control Module (TCM) is a computer that controls all the functions of your automatic transmission, from when to shift gears to how firmly it engages. It receives data from various sensors to make these decisions.
Is this part difficult to install myself?
For most DIYers, this is a very manageable job. It’s typically mounted in an accessible location in the engine bay and just requires unbolting the old unit and plugging in the new one. Always disconnect the battery first.
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. While a faulty TCM can cause a P0700, you should scan for more specific transmission codes (e.g., P07xx) to pinpoint the issue. This module often resolves the underlying cause of the P0700.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old part or dispose of it at your convenience without the hassle of sending it back.