Restore Smooth, Reliable Shifting to Your GM Vehicle
If your 2006 Chevrolet Trailblazer EXT is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, the problem often points directly to a failing Transmission Control Module (TCM). As a technician with over two decades of experience under the hood, I’ve seen countless drivers chase expensive and unnecessary repairs when the real culprit was this critical electronic component. This T42 TCM, interchangeable with part number 24241806, is the definitive solution to get your vehicle’s automatic transmission operating like new again.
The TCM is the brain of your transmission, responsible for interpreting data from sensors all over the vehicle to decide the exact moment to shift gears, engage the torque converter, and regulate fluid pressure. When it fails, the results can range from annoying (poor fuel economy, jerky shifts) to dangerous (unpredictable gear engagement, limp mode). Our modules are meticulously prepared and programmed to your specific Vehicle Identification Number (VIN), ensuring they work perfectly right out of the box. This eliminates the need for costly programming appointments at a dealership, saving you both time and money.
Case Study: The Ghost in the Transmission
A customer brought in a 2007 GMC Sierra with classic transmission failure symptoms: banging into gear and a P0752 (Shift Solenoid ‘A’ Stuck On) code. The previous shop had already replaced the solenoid twice, but the problem kept returning. After a quick data stream analysis, I noticed the command signals from the TCM were erratic. The solenoid was just following bad orders. We installed one of our VIN-programmed T42 modules, cleared the codes, and the truck shifted perfectly. The customer saved hundreds on what would have been a full transmission rebuild at another shop. This is a story I’ve seen play out with dozens of GM vehicles from this era.
Is Your Trailblazer Showing These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s time to consider a replacement. Ignoring these symptoms can lead to permanent damage to your transmission.
- âś” Harsh, delayed, or erratic shifting between gears.
- âś” The vehicle is stuck in “limp mode” (usually 2nd or 3rd gear).
- âś” Check Engine Light or Transmission Warning Light is illuminated.
- âś” Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750-P0758, or other solenoid-related faults.
- âś” Complete loss of upshifting or downshifting capabilities.
- âś” A noticeable drop in fuel efficiency.
- âś” Intermittent or total loss of communication with the scan tool.
A Straightforward Guide to Your TCM Replacement
For the confident DIYer or professional mechanic, installing this 2006 Trailblazer EXT TCM is a simple process that typically takes less than 30 minutes. The location varies by model, but it’s always accessible in the engine bay.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement. This prevents electrical shorts and helps reset the vehicle’s systems.
- Locate the Module: On your 2006 Trailblazer EXT, the TCM is found in the left-hand (driver’s side) engine compartment. On other GM vehicles, it might be next to the battery, under the air cleaner box, or on the RH side.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Once disconnected, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, VIN-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s best practice to use a standard OBD2 scan tool to clear any stored fault codes from the vehicle’s memory. Start the engine and take a test drive to confirm smooth shifting.
Verified Vehicle Compatibility List
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. It is interchangeable with part numbers 24252114, 24234503, 24230461, 24234274, 24241806, and more. Please verify your specific model and location below.
Partial Fitment List:
- Chevrolet Trailblazer / EXT (2006-2009): 8 cylinder, LH engine compartment
- GMC Envoy / XL (2006-2009): 8 cylinder, LH engine compartment
- Chevrolet Silverado 1500 (2007-2013): Next to battery
- GMC Sierra 1500 (2007-2013): Next to battery
- Chevrolet Tahoe / Suburban (2007-2009): Next to battery
- GMC Yukon / XL (2007-2009): Next to battery
- Chevrolet Impala (2006-2011): Lower air cleaner housing
- Chevrolet Cobalt / HHR (2006-2011): LH strut tower or engine compartment
- Pontiac G6 (2006-2010): LH strut tower
- Cadillac DTS (2006-2011): RH front engine compartment
- Hummer H3 (2008-2010): RH rear engine compartment
- Chevrolet Express / GMC Savana Vans (2006-2014): RH engine compartment
Frequently Asked Questions About Your 2006 Trailblazer EXT TCM
Do I need to do any programming after installation?
Do I need to do any programming after installation?
No. This module is delivered pre-programmed to your vehicle’s specific VIN. It is a true plug-and-play solution, saving you a trip to the dealership. Just install it, clear any old codes, and you’re ready to drive.
Is this a reliable, long-term fix?
Absolutely. We build our modules to meet or exceed OEM specifications using the latest GM software updates. This addresses common factory failure points, ensuring enhanced reliability and a long service life. It’s backed by our one-year warranty for your peace of mind.
How do I provide my VIN?
You will be prompted to enter your vehicle’s 17-digit VIN during the checkout process. This is crucial for us to program the module correctly for your specific vehicle configuration.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep your old module or dispose of it without any hassle or extra fees.