Is your 2006-2014 Chevrolet Express 3500 van exhibiting strange shifting behavior, getting stuck in gear, or showing transmission-related warning lights? These are classic signs of a failing Transmission Control Module (TCM). The TCM is the electronic brain of your automatic transmission, responsible for orchestrating every gear change, managing torque converter lockup, and monitoring system health. When it fails, it can lead to poor performance, decreased fuel economy, and potentially catastrophic transmission damage. Restore the reliability and smooth operation of your workhorse van with this direct-fit, VIN-programmed T42 TCM, part number 24240449.
From the Diagnostic Bay
We had a 2011 Savana 2500 (which uses the same powertrain as the Express) towed in last month. The owner, a local contractor, said it suddenly started slamming into gear and wouldn’t shift past 3rd. The check engine light was on, and his scanner showed a P0700 (Transmission Control System Malfunction) and a handful of solenoid circuit codes. He was worried he needed a full transmission rebuild. After a quick check of the fluid and wiring, we suspected the TCM. We installed one of our VIN-programmed T42 modules, cleared the codes, and took it for a test drive. The van shifted perfectly, just like new. It was a 30-minute fix that saved him thousands on an unnecessary transmission replacement.
Diagnosing Your 2006-2014 Express 3500 TCM
The T42 TCM in your Express 3500 is a critical component that communicates with the Engine Control Module (ECM) and various sensors to ensure your transmission is always in the right gear at the right time. Over time, heat cycles, vibrations, and electrical fluctuations can cause internal components to fail. This can manifest as intermittent issues that gradually worsen or a sudden, complete failure. If you’re experiencing any of the symptoms listed below, a faulty TCM is the most likely culprit.
Common Symptoms of a Failing GM T42 TCM
- ✔ Harsh or Erratic Shifting: Your van may slam into gear, hesitate between shifts, or shift at incorrect RPMs.
- ✔ Stuck in Limp Mode: The vehicle may refuse to shift out of a single gear (often 2nd or 3rd) to prevent further damage.
- ✔ Transmission Warning Lights: The Check Engine Light or a specific transmission warning light will illuminate on your dashboard.
- ✔ Diagnostic Trouble Codes (DTCs): You’ll find stored codes like P0700, P0750, or other solenoid-specific faults when using a scan tool.
- ✔ Delayed Engagement: A noticeable delay when shifting from Park to Drive or Reverse.
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter operation can lead to a significant drop in MPG.
- ✔ Complete Communication Loss: In severe cases, the TCM may stop communicating with the vehicle’s network, leading to a no-start condition or complete transmission failure.
This replacement module is the definitive solution to these problems. We pre-program each unit to your vehicle’s specific Vehicle Identification Number (VIN) before shipping. This crucial step ensures that the module has the correct software and calibrations for your Express 3500’s specific configuration, including engine size and axle ratio. The result is a true plug-and-play installation that requires no expensive trip to the dealership for programming. Simply install the module, clear any old codes, and get back on the road.
Frequently Asked Questions
What is a T42 Transmission Control Module?
The T42 is a specific generation of General Motors’ Transmission Control Module used in a wide variety of cars, trucks, and vans from the mid-2000s to the mid-2010s. It controls all electronic functions of 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L80E found in your Express van.
Do I need to program this module?
No. This module comes pre-programmed to your vehicle’s VIN. During checkout, you will provide your VIN, and we will flash the module with the latest GM software specific to your van. This makes installation a simple plug-and-play process without needing a dealership visit.
Is this part difficult to install on my Express 3500?
Installation is straightforward for someone with basic mechanical skills. On the Express and Savana vans, the TCM is typically located in the engine compartment on the right-hand (passenger) side. The process involves disconnecting the battery, unplugging the electrical connectors, unbolting the old module, and installing the new one. It usually takes less than 30 minutes.
Will this fix my P0700 diagnostic trouble code?
A P0700 code is a general fault code indicating that the TCM has detected a problem and has requested the Check Engine Light to be turned on. Often, a failing TCM is the root cause. Replacing the faulty module with this programmed unit will typically resolve the P0700 code and any related solenoid or sensor codes it was causing.
Is there a core charge for this part?
No, we do not require a core charge for this Transmission Control Module. You can keep your old part without the hassle of returning it.