If your 2007-2008 Chevrolet Avalanche 1500 is suffering from delayed shifts, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen countless GM trucks and SUVs sidelined by a faulty Transmission Control Module (TCM). The T42 module is the electronic brain of your automatic transmission, and when it fails, it can mimic a catastrophic transmission failure, leading to costly misdiagnoses. This replacement T42 TCM, part number 24230461, is the definitive solution to restore crisp, reliable shifting performance.
The biggest hurdle with electronic module replacement has always been the expensive and time-consuming trip to the dealership for programming. We eliminate that step entirely. We flash this module with your vehicle’s specific VIN before it ships, making it a true plug-and-play component. This ensures it communicates perfectly with your vehicle’s Powertrain Control Module (PCM) and other systems right out of the box, restoring factory shift points and torque converter lock-up strategy for optimal performance and fuel economy.
Is Your Avalanche Exhibiting These Telltale Signs?
A failing TCM can cause a host of frustrating and concerning issues. In my shop, these are the most common symptoms I trace back to a bad module. Check if any of these sound familiar:
- ✔ Jarring, hard shifts between gears or a noticeable slam when shifting from Park to Drive.
- ✔ The vehicle refuses to shift out of a single gear (often 2nd or 3rd), a condition known as “limp mode.”
- ✔ Your check engine light is on with Diagnostic Trouble Codes (DTCs) like P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid codes), or other transmission-related faults.
- ✔ Unexplained loss of fuel efficiency or the transmission seems to be overheating.
- ✔ Complete failure to engage gears or intermittent loss of communication with the module.
From the Diagnostic Bay
A customer brought in his ’08 Silverado 1500, a truck nearly identical to the Avalanche platform. He was convinced his 4L60E transmission was shot. It was stuck in 3rd gear, and he’d been quoted over $3,000 for a rebuild by another shop. After plugging in my scan tool, I saw a P0700 code and a series of solenoid communication errors. Instead of tearing down the transmission, I checked the TCM. After swapping in one of our pre-programmed modules—a 25-minute job—the truck shifted perfectly. He drove away with a reliable truck, having saved thousands. This is a classic case where the 2007-2008 Avalanche 1500 TCM is the simple, correct fix.
Your 30-Minute Path to Smooth Shifting
You don’t need to be a professional mechanic to install this part. The process is straightforward and can be done in your driveway with basic hand tools.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the onboard systems.
- Locate the Module: On the 2007-2008 Avalanche, the TCM is typically located in the engine bay, right next to the battery.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a click as they lock in.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a minute. While the module is plug-and-play, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the previous failure.
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct replacement for part number 24230461 and interchanges with several other service numbers. It is guaranteed to fit the following models, among others:
- Chevrolet Avalanche 1500 (2007-2008) – Located next to the battery
- Chevrolet Silverado & GMC Sierra 1500/2500 (2007-2013) – Located next to the battery
- Chevrolet Tahoe & GMC Yukon (2007-2009) – Located next to the battery
- Chevrolet Express & GMC Savana Vans (2006-2014) – Located in the RH engine compartment
- Cadillac DTS (2006-2011) – Located in the RH front engine compartment
- Hummer H3 (2008-2010) – Located in the RH rear engine compartment
- …and many other GM cars, trucks, and SUVs from 2006-2014. Please verify your specific model in the list below.
Frequently Asked Questions
What exactly does a Transmission Control Module do?
The TCM is a computer that processes data from vehicle sensors to control all aspects of your automatic transmission’s operation, including when to shift gears, how firmly to shift, and when to lock the torque converter. A faulty one directly impacts drivability and performance.
Why is VIN programming so important?
VIN programming loads your vehicle’s specific software and calibrations onto the module. Without it, the TCM won’t work correctly with your engine and transmission, leading to persistent shifting problems or a no-start condition. Our pre-programming service saves you a trip to the dealer and ensures immediate functionality.
Will this module fix my transmission codes like P0700?
Yes. If the codes are being caused by an electrical or internal failure of the original TCM, this replacement part is designed to resolve those issues. After installation, you should clear the codes with a scan tool.
Is this a difficult part for a DIYer to install?
Not at all. For most vehicles like the 2007-2008 Avalanche 1500, the TCM is easily accessible in the engine bay. With basic tools, most people can complete the swap in under 30 minutes, making it an excellent DIY-friendly repair.
Do I need to send my old part back?
No, there is no core charge for this module. You can keep or dispose of your old part without any hassle, simplifying your repair process.
What kind of warranty is included?
This module is backed by our one-year warranty, giving you confidence and peace of mind in the quality and reliability of your purchase.