If your 2007-2008 Chevrolet Avalanche 1500 is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Transmission Control Module (TCM) can bring a perfectly good truck to a standstill. The constant worry about whether your transmission will engage properly or leave you stranded is frustrating. This T42 TCM, part number 24240449, is the definitive solution to restore your truck’s performance and your peace of mind.
This isn’t just a replacement part; it’s a complete fix. We pre-program each module to your vehicle’s specific VIN before it ships. This crucial step eliminates the need for expensive trips to the dealership for programming. You get a true plug-and-play component that communicates flawlessly with your Avalanche’s powertrain, ensuring smooth gear changes, correct torque converter lockup, and reliable operation right out of the box. It’s designed to meet and exceed original equipment standards for a long-lasting repair.
Case Study: A Tricky Diagnosis
A customer brought in his ’08 Avalanche with a complaint that stumped a couple of other shops. It had intermittent, violent 1-2 shifts, but only after it was fully warmed up. There were no consistent codes, just a generic P0700 every now and then. We checked fluid levels, solenoids, and wiring harnesses—all looked fine. From experience, I know that heat-related electronic failures are common in these T42 modules. We swapped in one of our VIN-programmed TCMs, and the problem vanished instantly. The original module’s internal circuits were failing under thermal stress, a classic symptom this replacement part is built to prevent.
Is Your Avalanche Exhibiting These Transmission Problems?
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. Addressing it now can prevent further damage to your transmission’s mechanical components.
- ✔ Harsh, clunky, 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, or other solenoid-related faults.
- ✔ Failure to upshift or downshift, leading to poor acceleration and fuel economy.
- ✔ Intermittent loss of communication with the module (a scan tool will show U-codes).
A Straightforward Guide to a 30-Minute Install
Installing your new 2007-2008 Avalanche 1500 TCM is a simple process that most DIYers can complete in their own driveway. For the Avalanche, you’ll typically find the module located next to the battery in the engine compartment.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the Old TCM: Find the module mounted near the battery. It will have several large electrical connectors attached to it.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. Press the release tabs firmly. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely plug in the wiring harness connectors until they click.
- Reconnect and Verify: Reconnect the negative battery terminal. Start the vehicle and allow it to idle for a few minutes. If you have a basic scan tool, use it to clear any stored fault codes. Take a test drive to confirm smooth shifting.
Verified Compatibility for Your GM Vehicle
This T42 TCM is a direct replacement for part number 24240449 and is interchangeable with many other service numbers. While it’s the perfect fit for the 2007-2008 Avalanche 1500 TCM requirement, it also fits a wide range of other GM cars, trucks, and SUVs equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. Key compatible models include:
- ✔ Chevrolet Silverado, Tahoe, Suburban, Express Van, Colorado
- ✔ GMC Sierra, Yukon, Savana Van, Canyon
- ✔ Hummer H3
- ✔ Cadillac DTS, Buick LaCrosse, Lucerne
- ✔ Pontiac G6, Grand Prix, and many more from 2006-2014.
Frequently Asked Questions
Do I need to do any programming after I install this TCM?
No. This module is fully pre-programmed to your vehicle’s VIN before shipping. It is a plug-and-play installation with no need for a dealer visit or special programming tools.
What tools do I need for the installation?
You’ll only need basic hand tools, typically a socket set to disconnect the battery and unbolt the module. No specialized equipment is required.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module, so you don’t have to worry about the hassle and expense 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 engine computer. While a faulty TCM is a very common cause, this code can also be triggered by other transmission issues. Replacing a bad TCM will resolve the code if the module itself is the root cause.
How do I provide my VIN for programming?
You will be prompted to enter your vehicle’s 17-digit VIN during the checkout process. Please double-check it for accuracy to ensure perfect programming.