Restore Your Buick’s Smooth, Reliable Performance
If your 2006-2011 Buick Lucerne is suffering from harsh shifting, getting stuck in gear, or throwing transmission-related check engine lights, a failing Transmission Control Module (TCM) is the most likely culprit. As a mechanic with over two decades of experience, I’ve seen firsthand how a faulty TCM can turn a comfortable ride into a frustrating and unpredictable experience. This replacement T42-style TCM, part number 24239926, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
The TCM is the brain of your automatic transmission, controlling everything from shift points to torque converter lockup. When it fails, communication between the engine and transmission breaks down, leading to the drivability issues you’re experiencing. Our module restores that crucial link, ensuring your Lucerne shifts exactly as the manufacturer intended, improving both performance and fuel economy.
Case Study: A Tricky Diagnosis
I remember a 2008 Lucerne that came into the shop with a complaint of intermittent, hard 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode), but with no consistent check engine light. The owner had already replaced a shift solenoid with no luck. After connecting my scan tool, I noticed erratic data from the transmission sensors, but the sensors themselves tested fine. This pointed directly to the processing unit—the TCM. The internal circuit board had developed micro-fractures from years of heat cycles in the engine bay. We installed one of our VIN-programmed modules, and the car immediately shifted like new. It’s a classic failure mode for these vehicles, and this part is the reliable fix.
Is Your Buick Lucerne Showing These Telltale Signs?
A failing TCM doesn’t just get worse; it can cause damage to your transmission over time. If you notice any of the following, it’s time for a replacement:
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ Vehicle is stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light is on with codes like P0700, P0750, P0753, or other solenoid-related faults.
- ✔ The transmission refuses to upshift or downshift properly.
- ✔ A sudden drop in fuel efficiency.
- ✔ Intermittent loss of communication with the module, causing unpredictable behavior.
A Straightforward Guide to Installation
One of the best features of this module is its simple installation. Because we program it to your VIN before shipping, you can avoid a costly trip to the dealership. The entire process typically takes less than 30 minutes for a DIYer with basic tools.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the TCM: On the Buick Lucerne, the TCM is typically found in the engine compartment, on the driver’s side (LH side). It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical harnesses from the old module. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. Ensure they click into place.
- Reconnect and Verify: Reconnect the negative battery terminal. Start the vehicle and check for smooth shifting and ensure no warning lights are present. We recommend using a basic scan tool to clear any stored historical codes.
Guaranteed Fitment for Your Vehicle
This 2006-2011 Lucerne TCM is a direct-fit replacement for part number 24239926 and is interchangeable with a wide range of other GM service numbers. While it is guaranteed for the Lucerne, it also fits many other GM vehicles. Please verify your part number or contact us for fitment confirmation.
Fits Buick Lucerne Models:
- 2006-2007 Buick Lucerne (with 4.6L V8)
- 2008-2011 Buick Lucerne (All Engines)
Do I need to have this TCM programmed by a dealer?
Do I need to have this TCM programmed by a dealer?
No. We handle all the programming for you. Simply provide your vehicle’s VIN during checkout, and the module will arrive ready for immediate installation, saving you time and money.
Is this a new or used part?
This is a high-quality, OEM-standard replacement part that has been expertly tested and programmed. It is backed by our one-year warranty for your peace of mind.
What tools do I need for installation?
Installation typically requires only basic hand tools, such as a socket set and a wrench to disconnect the battery terminal. No special electronic equipment is needed.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request, meaning the TCM has detected a problem and asked the main computer to turn on the check engine light. In many cases, a faulty TCM is the root cause, and replacing it will resolve the P0700 code and any related specific transmission codes.
Is there a core charge?
No, there is no core charge for this part. You are not required to send your old module back, making the process hassle-free.