If your 2007 GMC Sierra 2500 is struggling with harsh shifts, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re dealing with a loss of reliability. As a technician with over two decades of experience under the hood of these trucks, I’ve seen firsthand how a failing Transmission Control Module (TCM) can bring a powerful workhorse to a grinding halt. The factory T42 TCM is the electronic brain of your 4L80E transmission, and when it starts to fail, the symptoms can be frustrating and even unsafe.
This isn’t just a replacement part; it’s a complete, hassle-free solution. We’ve eliminated the biggest headache of this repair: the trip to the dealership. This module arrives at your door pre-programmed to your truck’s specific Vehicle Identification Number (VIN). This ensures it communicates perfectly with your vehicle’s other systems right out of the box, restoring the precise, smooth shifting you depend on. Forget about expensive dealer programming fees or complex diagnostic tools—this is a direct-fit, plug-and-play fix for your 2007 Sierra 2500 TCM issues.
Is Your Sierra Exhibiting These Telltale Symptoms?
- ✔ Harsh, slamming shifts or erratic gear changes.
- ✔ The truck is stuck in “limp mode,” often in 2nd or 3rd gear.
- ✔ Check Engine Light is on with transmission-related Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid performance codes.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Failure to upshift or downshift, leading to poor acceleration and terrible fuel economy.
- ✔ Intermittent loss of communication with the TCM, causing unpredictable behavior.
From the Diagnostic Bay
I remember a customer bringing in his ’07 Sierra 2500 HD with a classic 6.0L. He was a contractor who relied on his truck daily. His complaint was baffling at first: sometimes the truck would shift perfectly, and other times it would slam into gear so hard it felt like he’d been rear-ended. He’d already replaced a shift solenoid with no luck. After connecting my scan tool, I saw a history of intermittent communication loss with the TCM. Heat soak in the engine bay was causing the module’s internal circuits to fail unpredictably. Installing a pre-programmed 2007 Sierra 2500 TCM didn’t just fix the shifting; it gave him back the dependable work truck he needed. This is a common story, and it’s why a quality, correctly programmed module is non-negotiable.
Straightforward Installation Guide for Your Sierra
Getting your truck back to peak performance is easier than you think. For most Sierra models, this is a simple job that takes less than 30 minutes. The TCM is typically located next to the battery in the engine compartment.
- Safety First: Always disconnect the negative terminal from your truck’s battery to prevent electrical shorts and reset the system.
- Locate the Module: Find the TCM, which is a silver box with electrical connectors, usually mounted on a bracket next to the battery.
- Disconnect and Remove: Carefully unplug the electrical harness connectors. They have locking tabs, so be gentle. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Mount the new, VIN-programmed module onto the bracket and securely reconnect the electrical harnesses. You should hear a click as they lock into place.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s always best practice to use a basic OBD2 scan tool to clear any stored fault codes from the system. Start the truck and enjoy smooth shifting!
Verified Vehicle Compatibility List
This T42 TCM, part number 24239224, is a direct replacement for a wide range of General Motors vehicles. While this page is focused on the 2007 Sierra 2500 TCM, it also fits the following models. Please verify your specific application.
Interchangeable Part Numbers: 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239926, 24240400, 24241806, 24243901, 24243921, 24255280, 24256960, 24235732, 24235753, 24240449, YNXS
This part will fit these makes and models with these options
SIERRA 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
SILVERADO 2500 PICKUP 07 Transmission; new style (smooth door skin), 6.0L, (next to battery)
… and many more GM vehicles from 2006-2014.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean for me?
It means the module is delivered ready for installation with no extra steps. We load your truck’s specific VIN onto the module before shipping, ensuring it works perfectly with your engine and transmission settings. This saves you hundreds of dollars and a trip to the dealership for programming.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request from the TCM to the Engine Control Module (ECM) to turn on the Check Engine Light. Often, a faulty TCM is the root cause. Replacing the module will typically clear the P0700 and any related specific codes (like for solenoids) if the TCM itself was the problem.
Do I need to send my old TCM back (core charge)?
No. There is no core charge for this part. You can keep your old module or dispose of it, making the process simpler and faster for you.
Is this a genuine GM part?
This is a high-quality replacement part built to meet or exceed OEM specifications for fit, form, and function. It is programmed using official GM software updates to ensure maximum compatibility and performance, backed by our one-year warranty.
Can I install this myself if I have basic tools?
Absolutely. For a 2007 Sierra 2500, the installation is very straightforward and located in an accessible spot in the engine bay. All you typically need is a basic socket set to remove the mounting bolts and your hands to disconnect the wiring. It’s an ideal repair for a confident DIYer.