Restore Smooth, Reliable Shifting to Your GMC Envoy
If you’re dealing with the headaches of a faulty transmission control module—like harsh shifting, getting stuck in gear, or a persistent check engine light—you’ve come to the right place. As a technician with over two decades of experience, I’ve seen firsthand how a failing TCM can make a reliable vehicle feel unpredictable. This T42 Transmission Control Module, part number 24240400, is the definitive solution for your 2006-2009 GMC Envoy and a wide range of other GM vehicles. It’s not just a replacement part; it’s a permanent fix that restores your vehicle’s factory performance and your peace of mind.
From the Diagnostic Bay: The Envoy That Wouldn’t Shift
A customer brought in his ’07 Envoy, complaining of intermittent, violent 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode). He’d already replaced a shift solenoid with no luck. His scanner showed a generic P0700 code. In my shop, I’ve diagnosed hundreds of these T42 modules. The internal circuit boards are prone to failure from heat cycles and vibration, causing erratic signals. We confirmed the solenoids were good and traced the issue to the TCM. By installing a VIN-programmed module like this one, we had him back on the road in under an hour, shifting perfectly. The pre-programming is key—it eliminates the communication errors that can persist even after a new part is installed.
The Critical Advantage: VIN Programming Included
The single biggest hurdle in replacing a modern electronic module is programming. Dealerships often charge hundreds for this service alone. We eliminate that step completely. Simply provide your vehicle’s VIN during checkout, and our experts will program this module with the latest GM software specific to your vehicle. This ensures it communicates flawlessly with your engine computer and other systems right out of the box. This isn’t a generic, one-size-fits-all solution; it’s a tailored fix for your specific 2006-2009 Envoy TCM requirements, guaranteeing optimal shift points, torque converter lockup, and fuel efficiency.
Is Your Envoy Exhibiting These Transmission Problems?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, this module is the likely solution:
- ✔️ Harsh, slamming, or delayed gear shifts.
- ✔️ Vehicle is stuck in “limp mode” and won’t shift out of 2nd or 3rd gear.
- ✔️ Check Engine Light or Transmission Warning Light is on with codes like P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔️ Failure to upshift or downshift, leading to poor acceleration.
- ✔️ A noticeable drop in fuel economy or signs of the transmission overheating.
- ✔️ Complete loss of communication with the transmission.
A Straightforward Guide to Installation
Designed for the confident DIYer and professional mechanic alike, this installation can be completed in your driveway with basic hand tools.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the onboard systems.
- Locate the Module: On the GMC Envoy, the TCM is typically found in the engine compartment on the driver’s side (LH side).
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs, as they can become brittle over time. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Reconnect the electrical harnesses securely, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. While our programming resolves most issues, it’s good practice to use a basic scan tool to clear any stored Diagnostic Trouble Codes (DTCs) from the vehicle’s memory.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number 24240400 and is interchangeable with a wide array of other service numbers. It is confirmed to fit the following models, among others:
- GMC Envoy: 2006-2009
- GMC Sierra 1500/2500/3500: 2007-2013
- GMC Yukon & Yukon XL: 2007-2009
- GMC Savana 1500/2500/3500: 2006-2014
- Chevrolet Silverado 1500/2500/3500: 2007-2013
- Chevrolet Tahoe & Suburban: 2007-2009
- Chevrolet Impala & Monte Carlo: 2006-2011
- Chevrolet Cobalt & HHR: 2006-2011
- Cadillac DTS: 2006-2011
- Buick LaCrosse & Lucerne: 2006-2011
- Pontiac G6 & Grand Prix: 2006-2010
- Hummer H3: 2008-2010
- Saab 9-7X: 2006-2009
This is not an exhaustive list. Please verify your part number or contact us with your VIN to ensure perfect fitment.
What information do you need to program the module?
What information do you need to program the module?
We require your vehicle’s 17-digit Vehicle Identification Number (VIN) to program the module with the correct software and calibrations for your specific application.
Is this a plug-and-play part?
Yes. Because we program it to your VIN before shipping, it is a true plug-and-play solution. No additional dealership visits or programming are required for installation.
Do I need any special tools to install this 2006-2009 Envoy TCM?
No special tools are needed. Basic hand tools like a socket set and ratchet are typically all that’s required for the installation, which usually takes less than 30 minutes.
Is there a core charge for my old part?
No, we do not require a core charge. You can keep your old module, which saves you the time and expense of shipping it back.
What kind of warranty is included?
This module is backed by our one-year warranty, covering any defects in materials or workmanship for your complete peace of mind.