Restore Your Van’s Shifting Performance
As a technician with over two decades of experience, I’ve seen countless work vans like the GMC Savana 3500 come into the shop with frustrating transmission problems. More often than not, the culprit isn’t a costly mechanical failure but a faulty Transmission Control Module (TCM). If your van is experiencing harsh shifting, getting stuck in gear, or throwing transmission codes, this VIN-programmed T42 TCM is the reliable, straightforward solution you need to get back on the road and back to work without delay.
This module is the electronic brain of your automatic transmission, controlling everything from shift points to torque converter lockup. When it fails, communication breaks down, leading to the symptoms that cripple your vehicle’s performance and fuel economy. We solve this by providing a high-quality replacement module, pre-programmed with your vehicle’s specific VIN. This eliminates the need for expensive dealership flashing or special tools, making it a true plug-and-play fix for professional mechanics and savvy DIYers alike.
A Technician’s Notebook: The Limp Mode Contractor
I remember a plumbing contractor whose 2011 Savana 3500 was stuck in limp mode (3rd gear only). He was losing money every hour the van was down. He suspected a full transmission rebuild was needed, but a quick scan showed a P0700 code and a series of solenoid circuit faults. We traced it to a failed TCM. Instead of a multi-day, multi-thousand-dollar repair, we swapped in a VIN-programmed T42 module in under 30 minutes. He drove out with smooth shifting and a van that was back to making him money. This part prevents that kind of costly downtime.
Diagnosing Your 2006-2014 Savana 3500 TCM
A failing TCM can mimic other transmission issues, but there are key indicators. The most common cause I’ve seen for failure on these T42 modules is internal circuit board breakdown from years of heat cycles and vibration, especially in hardworking commercial vehicles. This leads to intermittent signals and unpredictable behavior. If your symptoms are electrical in nature and inconsistent, the TCM is a prime suspect.
Is Your Van Showing These Symptoms?
- ✔️ Harsh, slamming shifts or delayed gear engagement.
- ✔️ Vehicle is stuck in “limp mode” and will not shift out of 2nd or 3rd gear.
- ✔️ Check Engine Light or Transmission Warning Light is on.
- ✔️ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0751, P0756, or other solenoid-related faults.
- ✔️ Sudden loss of power or poor acceleration.
- ✔️ Inconsistent or no communication with the TCM when using a scan tool.
- ✔️ Poor fuel economy due to incorrect gear selection or torque converter issues.
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- ✔ Locate the Module: On the Savana 3500 Van, the TCM is typically found in the engine compartment on the right-hand (passenger) side.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. Note the orientation of any locking tabs to avoid damage. Then, unbolt the old module from its mounting bracket.
- ✔ Install the New Module: Bolt the new, VIN-programmed TCM into place. Securely reconnect the electrical harnesses, ensuring they click into place.
- ✔ Final Steps: Reconnect the negative battery terminal. While our programming handles the critical setup, it’s best practice to use a basic OBD2 scan tool to clear any stored fault codes from the ECU. Start the vehicle and test drive to confirm smooth shifting.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number YNXS and other interchangeable numbers. It is engineered for a wide range of 2006-2014 General Motors vehicles equipped with 4-speed automatic transmissions (4L60E, 4L65E, 4L70E, 4L80E). While this page focuses on the Savana, fitment is confirmed for the following models:
Partial Fitment List: SAVANA 1500/2500/3500 VAN (06-14), EXPRESS 1500/2500/3500 VAN (06-14), SILVERADO/SIERRA 1500/2500 (07-13), TAHOE/YUKON (07-09), IMPALA (06-11), HHR (06-11), COLORADO/CANYON (08-12), and many more. Please verify your specific model and part number before ordering.
Do I need to take this part to a dealer for programming?
Do I need to take this part to a dealer for programming?
No. This Transmission Control Module comes pre-programmed to your vehicle’s VIN. This makes the installation process simple, saving you a trip to the dealership and additional programming fees. It’s ready to install right out of the box.
What is the warranty on this TCM?
This module is backed by our one-year, hassle-free warranty. We stand by the quality and reliability of our electronic components to give you peace of mind with your repair.
Is there a core charge for my old part?
No, we do not require a core charge. You can keep your old part without any extra fees or the hassle of shipping it back.
How do I know if my transmission is failing or just the TCM?
While symptoms can overlap, TCM failures are often electrical and intermittent. Look for multiple, seemingly unrelated solenoid codes (e.g., P0751, P0756) or a P0700 (Transmission Control System Malfunction) code. A complete loss of communication with the TCM via a scan tool is also a strong indicator. Mechanical failures often present with consistent noises (whining, grinding) or slipping that is directly related to engine RPM.