Restore Smooth Shifting to Your GMC Envoy
If your 2006-2009 GMC Envoy is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, the culprit is often a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen firsthand how a faulty TCM can mimic a major transmission failure, leading to stress and costly misdiagnoses. This OEM-quality T42 TCM, part number 24240400, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
The TCM is the electronic brain of your automatic transmission, controlling everything from shift points and line pressure to torque converter lockup. When it fails, communication breaks down, resulting in poor drivability and potential long-term damage. Our module restores that critical communication, ensuring your 4L60E or 4L65E transmission operates exactly as the factory intended, without a trip to the dealership for expensive programming.
From the Diagnostic Bay
I remember a customer with a 2008 Envoy who was told he needed a full transmission rebuild for over $3,000. His SUV was stuck in 3rd gear (limp mode) and had a P0700 code. After a quick scan, I suspected the TCM. We swapped in one of our VIN-programmed modules right in the parking lot. In less than 30 minutes, the vehicle was shifting perfectly, the check engine light was off, and the customer saved thousands. This isn’t just a part; it’s a solution that gets you back on the road with confidence.
Is Your Envoy Exhibiting These Transmission Faults?
A failing 2006-2009 Envoy TCM will make its presence known through a variety of symptoms. If you’re experiencing any of the following, it’s time to consider a replacement:
- ✔ Harsh, erratic, or delayed gear shifts.
- ✔ Vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ Failure to upshift or downshift properly.
- ✔ Decreased fuel economy and a feeling of sluggish performance.
- ✔ Intermittent loss of communication with the module.
A Straightforward Guide to Installation
One of the best features of this module is its simple, DIY-friendly installation. No specialized tools are required, and the process typically takes less than 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the Module: On the GMC Envoy and related platforms, the TCM is typically found in the engine compartment on the driver’s side (LH side).
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, 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. Ensure they click into place.
- Reconnect and Verify: Reconnect the negative battery terminal. Start the vehicle and check for smooth shifting and ensure no warning lights are present. We recommend using a basic scan tool to clear any stored historical codes.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number 24240400 and is interchangeable with many other GM service numbers. While it is a guaranteed fit for the 2006-2009 Envoy TCM application, it also fits a wide range of other GM vehicles, including:
- GMC: Envoy (06-09), Sierra 1500/2500 (07-13), Yukon (07-09), Savana Vans (06-14), Canyon (08-12)
- Chevrolet: Silverado 1500/2500 (07-13), Tahoe (07-09), Suburban (07-08), Avalanche (07-08), Express Vans (06-14), Colorado (08-12), Cobalt (06-10), HHR (06-11), Impala (06-11), Malibu (06-10), Monte Carlo (06-07)
- Buick: LaCrosse (06-09), Lucerne (06-11), Rainier (06-07), Rendezvous (06-07)
- Cadillac: DTS (06-11)
- Pontiac: G5 (07-10), G6 (06-10), Grand Prix (06-08)
- Saturn: Aura (07-09), Ion (06-07), Vue (07-10)
- Hummer: H3 (08-10)
- Saab: 9-7X (06-09)
Frequently Asked Questions
What does “VIN Programmed” mean for me?
It means this module is delivered ready for installation. We flash it with your vehicle’s unique VIN and the latest GM software, so it communicates perfectly with your engine and transmission right out of the box. No expensive dealer programming is needed.
Is a core charge required for my old TCM?
No, there is no core charge. You can keep your old part, which saves you the time and hassle of shipping it back.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main computer (PCM) to turn on the check engine light. While this module often resolves the underlying issue causing the P0700, you should scan for more specific codes (like P0753, P0758, etc.) to confirm the diagnosis. In many cases, a faulty TCM is the root cause.
How do I know this is the correct part for my Envoy?
This module is the correct fit for 2006-2009 GMC Envoy models. To be 100% certain, you can match the part number 24240400 from your existing module or simply provide your VIN at checkout, and we will guarantee compatibility.