Is Your GMC Sierra Shifting Erratically?
If you’re dealing with harsh shifts, delayed gear engagement, or a check engine light that points to transmission trouble in your 2007-2013 GMC Sierra 1500, a failing Transmission Control Module (TCM) is a likely culprit. The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every gear change, managing torque converter lockup, and ensuring the powertrain operates smoothly. When it fails, it can cause a host of frustrating and potentially damaging issues, from poor fuel economy to being stuck in ‘limp mode’.
This genuine GM T42 Transmission Control Module, service part number 24240449, is the definitive solution. We pre-program each module to your truck’s specific Vehicle Identification Number (VIN) before shipping. This critical step ensures complete compatibility with your vehicle’s systems, eliminating the need for an expensive trip to the dealership for programming. It arrives ready for a straightforward, plug-and-play installation.
From the Diagnostic Bay
We had a 2008 Silverado come in that was stuck in third gear. The owner had already replaced two shift solenoids based on some generic trouble codes, but the problem persisted. Upon scanning, we saw the classic P0700 code, which is just a general fault request from the TCM. Digging deeper, we found intermittent communication loss with the module. Instead of throwing more parts at the transmission itself, we inspected the TCM. We found no external damage, but experience pointed to an internal electronic failure. We installed one of our VIN-programmed T42 modules, cleared the codes, and the truck was shifting perfectly within 30 minutes. It’s a common scenario where the ‘brain’ is the issue, not the mechanical parts it controls.
Symptoms of a Failing Sierra 1500 Transmission Module
- ✔️ Harsh or Erratic Shifting: Your truck may slam into gear, hesitate between shifts, or feel unpredictable during acceleration.
- ✔️ Stuck in Gear / Limp Mode: The transmission may refuse to shift out of a single gear (often 2nd or 3rd) to prevent further damage.
- ✔️ Warning Lights: The Check Engine Light or a specific transmission warning light will illuminate on your dashboard.
- ✔️ Diagnostic Trouble Codes (DTCs): You’ll often see codes like P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (e.g., P0751, P0756).
- ✔️ Poor Fuel Economy: Inefficient shifting and failure to engage the torque converter lockup can cause a noticeable drop in MPG.
- ✔️ No Communication: In severe cases, a scan tool may be unable to communicate with the TCM at all, indicating a complete module failure.
The Advantage of a Pre-Programmed T42 TCM
This isn’t just a replacement part; it’s a complete, ready-to-install solution. The key is our VIN programming service. Modern vehicles use complex networks where modules must recognize each other to function. By programming the module with your truck’s VIN, we load the latest GM software and ensure it communicates flawlessly with the Engine Control Module (ECM) and other vehicle systems right out of the box. This restores original performance and shift strategies intended by the manufacturer.
Installation and Compatibility
Installation is simple for a DIY mechanic or any professional technician. On most GMC Sierra and Chevrolet Silverado models from this era, the TCM is located in the engine bay, typically next to the battery or under the air cleaner box. The process involves disconnecting the battery, unplugging the electrical connectors from the old module, unbolting it, and installing the new one in its place. Once connected, reconnect the battery, and you’re ready to go. We recommend clearing any stored DTCs with a scan tool after installation.
This module is a direct replacement for a wide range of part numbers, including 24252114, 24234503, 24230461, and many more. It fits not only the Sierra 1500 but also a vast array of other GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E, such as the Chevrolet Tahoe, Suburban, Express Van, GMC Yukon, and Cadillac DTS.
Frequently Asked Questions
What does a T42 Transmission Control Module do?
The T42 TCM is an electronic computer that acts as the brain for your automatic transmission. It receives data from various sensors (like vehicle speed, throttle position, and engine RPM) and uses this information to control shift solenoids, regulate hydraulic pressure, and manage the torque converter clutch, ensuring smooth and efficient gear changes.
Why is VIN programming so important for this part?
VIN programming loads your vehicle’s specific software, including shift points, torque strategies, and communication protocols. Without it, a new module won’t recognize your vehicle’s other computers, leading to a no-start condition, incorrect shifting, or persistent error codes. Our pre-programming service makes the part plug-and-play, saving you a trip to the dealer.
Can I install this module myself?
Yes, this is a very DIY-friendly repair for those with basic mechanical skills. The module is typically located in an accessible part of the engine bay. The process involves disconnecting the battery, swapping the modules, and reconnecting everything. The entire job usually takes less than 30 minutes.
Will this fix a P0700 diagnostic trouble code?
A P0700 code is a general code indicating that the TCM has detected a fault and has requested the Check Engine Light to be turned on. While a faulty TCM itself can cause a P0700, this code is often accompanied by other, more specific codes. If your diagnostics point to an internal TCM failure or communication error, this module is the correct fix.
Is there a core charge for this part?
No, we do not require you to return your old, faulty module. There is no core charge associated with this purchase, saving you time and the hassle of shipping back the old part.