Is your 2007-2008 Chevrolet Avalanche 1500 shifting erratically, getting stuck in gear, or throwing transmission codes? As a mechanic with over two decades of experience, I’ve seen these symptoms countless times, and they almost always point to a failing Transmission Control Module (TCM). A faulty TCM can make your reliable truck feel unpredictable and unsafe. This isn’t just an annoyance; it’s a critical failure that can lead to more significant transmission damage if ignored.
This T42 Transmission Control Module, part number 24240449, is the definitive solution. We pre-program it to your truck’s specific Vehicle Identification Number (VIN) before shipping. This means it arrives ready for a true plug-and-play installation, eliminating the need for expensive and time-consuming programming at a dealership. Restore the crisp, smooth shifting and reliable performance your Avalanche was built for.
Diagnosing a Faulty GM Transmission Module
- ✔ Your truck slams into gear or shifts at the wrong times.
- ✔ The transmission feels like it’s slipping, or there’s a long delay when shifting from Park to Drive.
- ✔ Your dashboard is lit up with a Check Engine Light or a transmission warning message.
- ✔ A scan tool reveals Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults.
- ✔ The vehicle is stuck in “limp mode,” often locked in 2nd or 3rd gear, with severely limited power.
- ✔ You’re experiencing a sudden drop in fuel economy or notice the transmission running hotter than usual.
From the Diagnostic Bay: The Silverado That Wouldn’t Shift
A customer brought in a 2008 Silverado with the classic 4L60E complaint: harsh 1-2 shifts and occasionally getting stuck in 3rd gear. He’d already replaced two shift solenoids himself, but the problem persisted. His scanner showed a P0752 (Shift Solenoid A Stuck On). After confirming the solenoids and wiring were good, we honed in on the TCM. In these GM trucks, the TCM’s internal drivers can fail, sending incorrect signals. We installed a VIN-programmed module just like this one. The total time on the lift was less than an hour, and the truck shifted perfectly on the test drive. It’s a common story, and this part is the reliable fix that saves you from chasing phantom electrical gremlins.
A Straightforward Guide to Installation
Replacing the 2007-2008 Avalanche 1500 TCM is a job most DIYers can handle in their driveway in about 30 minutes. The module is typically located next to the battery in the engine compartment.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent electrical shorts and help reset the vehicle’s electronic systems.
- Locate the Module: On your Avalanche, find the TCM mounted next to the battery. It’s a silver box with several large electrical connectors.
- Disconnect and Remove: Carefully unclip the wiring harnesses. They have locking tabs, so don’t force them. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the wiring harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s always good practice to use a basic scan tool to clear any stored fault codes from the vehicle’s memory. Start the truck and enjoy a smooth ride!
Verified Vehicle Compatibility
This module is a direct replacement for part number 24240449 and is compatible with a wide array of 2006-2014 General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page is focused on the 2007-2008 Avalanche 1500 TCM, it also fits many other models. Please see the detailed fitment list to confirm it’s the right part for your specific truck, van, or SUV.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean?
It means we load your vehicle’s unique VIN into the module before it ships. This ensures the TCM has the correct software and settings for your truck’s specific configuration (engine, axle ratio, tire size), allowing it to work perfectly right out of the box without a dealer visit.
Do I need to send my old TCM back?
No, there is no core charge for this part. You can keep your old module or dispose of it responsibly.
Will this fix a P0700 code?
A P0700 is a generic code indicating the TCM has detected a fault. Often, replacing a failed TCM will resolve the underlying issue causing the P0700. However, you should always diagnose the specific codes stored within the TCM (like solenoid or sensor codes) to confirm the module is the root cause.
Is this an OEM part?
This is a high-quality replacement part built to meet or exceed original equipment manufacturer (OEM) specifications for performance and reliability. It comes with a one-year warranty for your peace of mind.
Where is the TCM located on my 2007 Avalanche?
On the 2007-2008 Chevrolet Avalanche 1500, the Transmission Control Module is conveniently located in the engine bay, right next to the battery. This makes for a very accessible and quick replacement.