If your 2007 or 2008 Chevrolet Avalanche 1500 is giving you trouble—slamming into gear, refusing to shift, or throwing transmission codes—you’ve come to the right place. As a technician with over two decades of experience under the hood, I can tell you that these symptoms almost always point to one culprit: a failing Transmission Control Module (TCM). This isn’t just an annoyance; it’s a critical failure that can leave you stranded. The TCM is the electronic brain of your automatic transmission, and when it malfunctions, your truck’s performance and reliability go right out the window.
We offer a dependable and straightforward solution: a high-quality replacement T42 Transmission Control Module, part number 24256960. The best part? It arrives at your door fully programmed to your truck’s specific Vehicle Identification Number (VIN). This means you can skip the expensive trip to the dealership for programming. It’s a true plug-and-play fix designed to get you back on the road with the smooth, predictable shifting you expect from your Avalanche.
Case Study: A Tricky Diagnosis
A customer brought in his ’08 Silverado with classic transmission failure symptoms: stuck in 3rd gear (limp mode) and a check engine light. He was convinced he needed a full transmission rebuild, a quote that ran into the thousands. I hooked up my scan tool and pulled a P0752 code (Shift Solenoid ‘A’ Stuck On). While this can be a solenoid issue, my experience with these GM trucks pointed me elsewhere. I checked the wiring and found no issues. On a hunch, I swapped in one of our pre-programmed TCMs. In less than 20 minutes, the code was gone, and the truck was shifting perfectly. The original TCM had an internal fault, sending bad signals. This simple part saved my customer a massive, unnecessary repair bill.
Is Your Avalanche Showing These Symptoms?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s highly likely this module is the root cause of your problems.
- ✔ Unpredictable, harsh, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear, often called “limp mode.”
- ✔ Check Engine Light or Transmission Warning Light is illuminated on your dash.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as the general code P0700 or specific solenoid codes (e.g., P0751, P0756).
- ✔ A noticeable drop in fuel economy as the transmission isn’t operating efficiently.
- ✔ Complete loss of communication with the transmission.
Get Your Avalanche Shifting Smoothly in Under 30 Minutes
One of the biggest benefits of this part is the ease of installation. For the 2007-2008 Avalanche 1500 TCM, the module is conveniently located in the engine bay, right next to the battery. You don’t need a vehicle lift or specialized transmission tools.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement.
- Locate the TCM: On your Avalanche, open the hood and find the TCM mounted next to the battery.
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely plug in the electrical connectors until they click.
- Reconnect and Verify: Reconnect the negative battery terminal. Start the vehicle and ensure there are no warning lights. A short test drive will confirm that shifting performance is restored.
Verified Fitment for Your GM Vehicle
While this is the correct part for your 2007-2008 Avalanche 1500, this T42 TCM is also compatible with a wide range of other General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. Please verify your specific model and part number. This module is interchangeable with service numbers 24242391, 24234503, 24252114, and many others.
This part will fit these makes and models with these options
AVALANCHE 1500 07-08 Transmission; (next to battery)
ALLURE 06-09 Transmission; (lower air cleaner housing)
AURA 07-09 Transmission; (LH frame rail front)
CANYON 08-12 Transmission; (RH rear engine compartment)
COBALT 06-10 Transmission; (LH strut tower)
COLORADO 08-12 Transmission; (RH rear engine compartment)
DTS 06-11 Transmission; (RH front engine compartment)
ENVOY 06-07 Transmission; (LH engine compartment), (8 cylinder)
ENVOY 08-09 Transmission; (LH engine compartment)
ENVOY XL 06 Transmission; (LH engine compartment), (8 cylinder)
EXPRESS 1500 VAN 06-14 Transmission; (RH engine compartment)
EXPRESS 2500 VAN 06-14 Transmission; (RH engine compartment)
EXPRESS 3500 VAN 06-14 Transmission; (RH engine compartment)
G5 07-10 Transmission; (LH strut tower)
G6 06-10 Transmission; (LH strut tower)
GRAND PRIX 06-08 Transmission; (lower air cleaner housing)
HHR 06-11 Transmission; (LH engine compartment)
HUMMER H3 08-10 Transmission; (RH rear engine compartment)
IMPALA 06-11 Transmission; (lower air cleaner housing)
ION 06-07 Transmission; (behind LH strut tower)
LACROSSE 06-09 Transmission; (lower air cleaner housing)
LUCERNE 06-07 Transmission; (4.6L), (LH engine compartment)
LUCERNE 08-11 Transmission; (LH engine compartment)
MALIBU 06-10 Transmission; (LH frame rail)
MONTE CARLO 06-07 Transmission; (lower air cleaner housing)
MONTANA 06-09 Transmission; (LH strut tower)
PURSUIT 06 Transmission; (LH strut tower)
RAINIER 06-07 Transmission
RENDEZVOUS 06-07 Transmission; (air cleaner box)
SAAB 9-7X 06-09 Transmission; (LH engine compartment)
SAVANA 1500 VAN 06-14 Transmission; (RH engine compartment)
SAVANA 2500 VAN 06-14 Transmission; (RH engine compartment)
SAVANA 3500 VAN 06-14 Transmission; (RH engine compartment)
SIERRA 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
SIERRA 1500 PICKUP 08 Transmission; (next to battery)
SIERRA 1500 PICKUP 09-13 Transmission; (next to battery), w/o hybrid option
SIERRA 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
SILVERADO 1500 PICKUP 07 Transmission; (new style, smooth door skin), (next to battery)
SILVERADO 1500 PICKUP 08 Transmission; (next to battery)
SILVERADO 1500 PICKUP 09-13 Transmission; (next to battery), w/o hybrid option
SILVERADO 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
SSR 05-06 Transmission; (front LH frame)
SUBURBAN 1500 07-08 Transmission; (next to battery)
TAHOE 07 Transmission; (next to battery)
TAHOE 08-09 Transmission; (next to battery), w/o auxiliary oil cooler pump
TERRAZA 06-07 Transmission; (LH strut tower)
TRAILBLAZER 06-07 Transmission; (LH engine compartment), (8 cylinder)
TRAILBLAZER 08-09 Transmission; (LH engine compartment)
TRAILBLAZER EXT 06 Transmission; (LH engine compartment), (8 cylinder)
UPLANDER 06-09 Transmission; (LH strut tower)
VUE 07-08 Transmission; 2.4L, (LH front engine compartment)
VUE 09 Transmission; 2.4L, w/hybrid, LH side front engine compartment, (shift control)
VUE 09 Transmission; 2.4L, w/o hybrid; (LH front engine compartment)
VUE 10 Transmission
YUKON 07 Transmission; (next to battery)
YUKON 08 Transmission; (next to battery), w/o auxiliary oil cooler control
YUKON 09 Transmission; (next to battery), w/o auxiliary oil cooler pump
YUKON XL 1500 07-08 Transmission; (next to battery)
Frequently Asked Questions
Do I need to take this part to a dealer after I install it?
Absolutely not. We program the module to your vehicle’s VIN before shipping it. This ensures it communicates correctly with your truck’s other systems right out of the box, saving you time and money.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old part or dispose of it at your convenience. We want to make the repair process as simple as possible for you.
What if I have other codes besides P0700?
A failing TCM is often the source of multiple transmission-related DTCs, especially those for solenoids or pressure switches. Replacing the faulty 2007-2008 Avalanche 1500 TCM will typically resolve these related codes once the new module is installed.
What kind of warranty comes with this TCM?
This module is backed by our one-year warranty. We stand behind the quality and reliability of our parts, giving you peace of mind for your repair.