If your 2007-2008 Chevrolet Avalanche 1500 is suffering from erratic shifting, 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 sideline an otherwise perfectly good truck. This isn’t just an annoyance; it’s a reliability issue that can leave you stranded. This T42 TCM is the definitive, hassle-free solution, arriving pre-programmed to your truck’s specific VIN for a true plug-and-play repair.
Forget about expensive dealership visits for programming. We handle that for you. By flashing the module with the latest GM software updates tied to your vehicle, we ensure it communicates flawlessly with your engine and transmission right out of the box. This restores the precise, smooth shifting characteristics your Avalanche had from the factory, improves fuel economy, and eliminates those frustrating warning lights on your dash. This is the same fix I’ve performed countless times in my own shop to get customers back on the road with confidence.
Is Your Avalanche Exhibiting These Transmission Issues?
- âś” Harsh, jerky, or delayed gear shifts that make driving uncomfortable.
- âś” The vehicle is stuck in “limp mode,” often refusing to shift out of 2nd or 3rd gear.
- âś” Check Engine Light or Transmission Warning Light is on, with Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults.
- âś” Inconsistent upshifting or downshifting, or a complete failure to shift at all.
- âś” A noticeable drop in fuel efficiency or signs of the transmission overheating.
- âś” Intermittent loss of communication with the TCM, causing unpredictable behavior.
Case Study: A Tricky Diagnosis
A customer brought in a 2007 Silverado with a complaint that stumped two other shops: intermittent, violent downshifts when coming to a stop, but no consistent codes. We checked the fluid, solenoids, and wiring—all perfect. On a hunch, I monitored the TCM data stream on a long test drive. I saw the output signals to the solenoids drop out for a split second, just before the harsh shift. It was a classic internal TCM failure caused by heat and vibration. We installed a VIN-programmed T42 module, and the problem was gone for good. This is why a quality, correctly programmed 2007-2008 Avalanche 1500 TCM is so critical; it solves the root electrical cause, not just the symptoms.
A Straightforward Guide to Installation
- âś” Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts and to help reset the vehicle’s electronic systems.
- âś” Locate the Module: On your 2007-2008 Avalanche, the TCM is typically located in the engine compartment, mounted next to the battery.
- âś” Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Then, unbolt the module from its mounting bracket.
- âś” Install the New TCM: Mount the new, pre-programmed module in place and securely fasten the bolts. Reconnect the electrical harnesses, ensuring they click into place.
- âś” Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s best practice to use a standard OBD2 scan tool to check for and clear any stored diagnostic codes to ensure a clean slate.
Verified Vehicle Compatibility
This module, part number 24239926, is a direct replacement for a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page focuses on the 2007-2008 Avalanche 1500 TCM, it is also a compatible fit for the following models. Please verify the location noted for your specific vehicle:
- Chevrolet Avalanche 1500 (2007-2008): Transmission; (next to battery)
- Chevrolet Silverado & GMC Sierra 1500/2500 (2007-2013): Transmission; (next to battery)
- Chevrolet Tahoe & GMC Yukon (2007-2009): Transmission; (next to battery)
- Chevrolet & GMC Express/Savana Vans (2006-2014): Transmission; (RH engine compartment)
- Cadillac DTS (2006-2011): Transmission; (RH front engine compartment)
- Hummer H3 (2008-2010): Transmission; (RH rear engine compartment)
- …and many other GM cars, trucks, and SUVs from 2006-2014.
Do I need to have this TCM programmed by a dealer?
Do I need to have this TCM programmed by a dealer?
No. The main benefit of our service is that we pre-program the module to your vehicle’s VIN before shipping. This means it’s ready for installation right out of the box, saving you the time and expense of a dealership visit.
Is this a difficult part to install myself?
For most DIYers with basic tools, this is a very manageable job. The TCM is typically easy to access in the engine bay, and the process involves disconnecting the battery, unplugging a few connectors, and removing a few bolts. The entire replacement can often be done in under 30 minutes.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request from the TCM to the ECM to turn on the check engine light. While a failing TCM is a very common cause, this code can also be triggered by other transmission issues. However, if you’re also experiencing symptoms like erratic shifting or limp mode, a faulty TCM is the most likely culprit.
Is there a core charge for this part?
No, there is no core charge. You are not required to send your old, faulty module back to us, which simplifies the process for you.