Is Your Savana 2500 Shifting Erratically?
If your 2006-2014 GMC Savana 2500 is experiencing harsh shifting, delayed gear engagement, or has the check engine light illuminated with transmission-related codes, a failing Transmission Control Module (TCM) is the most likely culprit. 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 leave your work van feeling unreliable and unsafe, potentially even stranding you in ‘limp mode’. This replacement T42 TCM, part number 24241806, is the definitive solution to restore your vehicle’s performance and peace of mind.
From the Diagnostic Bay
We had a 2011 Express van come into the shop with classic symptoms of a bad transmission—slipping between 2nd and 3rd gear and a P0751 code for Shift Solenoid ‘A’ Stuck Off. The previous mechanic had already replaced the solenoid twice with no success. After a quick data scan, we noticed the command signals from the TCM were intermittent. The issue wasn’t the solenoid itself, but the module failing to control it properly. We installed a VIN-programmed T42 module, cleared the codes, and the van shifted perfectly. It’s a classic case where diagnosing the root cause—the controller—saved the customer from a costly and unnecessary transmission rebuild.
Diagnosing a Faulty Savana 2500 Transmission Module
The T42 TCM is a critical component for vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L80E. Failure can manifest in various ways, often mimicking mechanical transmission problems. Before condemning your transmission, check for these common electronic failure symptoms.
Symptoms of a Failing T42 TCM
- ✔ Harsh or Delayed Shifting: Your van may slam into gear, hesitate before shifting, or feel like it’s slipping between gears.
- ✔ 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 dedicated transmission warning light will often be active on the dashboard.
- ✔ Diagnostic Trouble Codes (DTCs): You’ll likely find codes such as P0700 (Transmission Control System Malfunction) or specific solenoid codes (P0750-P0774).
- ✔ Poor Fuel Economy: Inefficient shifting and incorrect torque converter lockup can lead to a noticeable drop in MPG.
- ✔ No Communication: In severe cases, a scan tool may be unable to communicate with the TCM, indicating a complete module failure.
The Plug-and-Play Advantage: VIN Programming Included
One of the biggest hurdles in replacing modern vehicle electronics is the need for expensive dealership programming. This module eliminates that step entirely. We pre-program each TCM to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This process loads the latest GM software and ensures the module is perfectly calibrated for your Savana’s engine, transmission, and tire size. The result is a true plug-and-play installation—no extra tools, no trip to the dealer, and no hidden fees. Simply install the module, and you’re ready to go.
Simple Installation Process
Replacing the TCM is a straightforward job that can typically be completed in under 30 minutes with basic hand tools. On the GMC Savana and Chevrolet Express vans, the module is conveniently located in the engine compartment on the right-hand (passenger) side.
- Safety First: Always disconnect the negative battery terminal before beginning any electrical work. This prevents short circuits and helps reset the vehicle’s electronic systems.
- Locate the TCM: Find the module on the RH side of the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs, as they can become brittle over time. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, VIN-programmed TCM into place and securely reconnect the wiring harnesses.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s best practice to use a scan tool to clear any stored DTCs from the vehicle’s memory to ensure a clean slate.
This module is a direct replacement for a wide range of GM vehicles and interchanges with numerous part numbers, including 24252114, 24234503, 24230461, 24240400, and more, ensuring broad compatibility for your repair needs.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean?
It means we load your vehicle’s unique 17-digit VIN into the module before shipping. This configures the TCM with the correct software and calibrations for your specific engine, transmission, and options, making it ready for installation right out of the box without needing a trip to the dealership.
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, which saves you the time, cost, and hassle of return shipping.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While a faulty TCM can cause this code, it often appears alongside more specific codes (like for a solenoid circuit). If the TCM itself is the source of the electrical fault, replacing it will resolve the code.
Is this a difficult part to replace myself?
For most DIYers with basic tools, this is a very manageable job. The module is typically easy to access in the engine bay, and the process involves simply unplugging connectors and removing a few bolts. The pre-programming saves you the most complex part of the job.
How can I be sure the TCM is the problem and not the transmission?
While a definitive diagnosis requires a professional scan tool, common indicators point to the TCM. If you have multiple, seemingly random solenoid codes, intermittent communication with the module, or shifting problems that are erratic and not consistent, the issue is more likely electronic (the TCM) than mechanical (internal transmission components).