If your 2006-2014 GMC Savana 3500 is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re losing time and money. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can bring a reliable workhorse to a dead stop. This T42 TCM, part number 24235754, is the definitive solution, arriving pre-programmed to your van’s specific VIN for a true plug-and-play repair that gets you back on the job without a costly trip to the dealership.
This module is the electronic brain of your automatic transmission, controlling everything from shift points to torque converter clutch engagement. When it fails, the symptoms can often be misdiagnosed as a more severe internal transmission issue. By replacing your faulty unit with this quality-tested module, you restore the precise, factory-intended operation of your 4L80E or other compatible GM transmission, ensuring reliability for the long haul.
From the Diagnostic Bay: The ‘Phantom’ Shifting Problem
A local contractor brought in his Savana 3500 work van, complaining of intermittent, violent shifts and occasionally getting stuck in 3rd gear (limp mode), but only after the van was fully warmed up. He’d already spent money on a transmission fluid flush, which didn’t help. We scanned it and found a generic P0700 code. In my shop, I’ve learned that heat-related electronic failures are common in these T42 TCMs. The internal circuits degrade over time and fail under thermal stress. We installed a VIN-programmed 2006-2014 Savana 3500 TCM, and the van was shifting perfectly within an hour. It’s a classic case where the right part saves the customer from a needless, expensive transmission rebuild.
Common Red Flags of a Failing Savana TCM
A failing TCM will give you clear warning signs. If you’re experiencing any of the following, it’s highly likely your module is the culprit:
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ Vehicle is stuck in “limp mode” and will not shift out of 2nd or 3rd gear.
- ✔ The Check Engine Light or a dedicated transmission warning light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid Errors), or other communication codes.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ Complete loss of communication with the transmission module.
Your 30-Minute Path Back to Smooth Shifting
For the professional mechanic or the confident DIYer, installation is straightforward. This module is designed for a direct swap, and because it’s pre-programmed, you eliminate the need for expensive scan tools or dealership intervention.
- 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/Express vans, the TCM is typically found in the engine compartment on the right-hand (passenger) side.
- Disconnect and Remove: Carefully unplug the electrical connectors. Use a socket wrench to remove the bolts holding the old TCM in place.
- Install the New Module: Mount your new, VIN-programmed TCM and securely fasten the bolts. Reconnect the electrical harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic scan tool to clear any stored DTCs from the vehicle’s memory. Start the engine and test drive to confirm smooth shifting.
Confirmed Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24235754 and interchanges with numerous other GM service numbers. It is compatible with a wide range of vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, 4L70E, and 4L80E. While this page focuses on the 2006-2014 Savana 3500 TCM, it also fits the following models:
- GMC: Savana 1500/2500/3500, Sierra 1500/2500, Yukon, Yukon XL, Envoy, Canyon
- Chevrolet: Express 1500/2500/3500, Silverado 1500/2500, Tahoe, Suburban, Avalanche, Impala, Monte Carlo, Cobalt, HHR, Colorado, SSR
- Buick: LaCrosse, Lucerne, Allure, Rainier, Rendezvous
- Cadillac: DTS
- Pontiac: G5, G6, Grand Prix, Pursuit
- Saturn: Vue, Aura, Ion
- Hummer: H3
- Saab: 9-7X
Note: Always verify fitment by part number or by using our vehicle selector tool to ensure 100% compatibility. Location may vary by model (e.g., next to battery, under air cleaner box).
Frequently Asked Questions
Is this part really plug-and-play?
Yes. We program the module with the latest GM software using the VIN you provide during checkout. This ensures it communicates perfectly with your vehicle’s other systems right out of the box, with no additional programming required.
Do I need any special tools to install this?
No special tools are needed. Basic hand tools like a socket set are all that’s required for the physical installation. A simple OBD2 scanner is helpful for clearing old codes, but not mandatory for the module to function.
Will this fix a P0700 code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause (like an internal short or failed driver), it’s important to ensure the transmission wiring and solenoids are also in good condition. In a vast majority of cases I’ve diagnosed, the TCM itself is the failure point.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of shipping it back to us.
What if I order the wrong part?
We’re here to help! Our expert support team can verify fitment before you buy. If you still run into an issue, we have a straightforward return policy and a one-year warranty to ensure you get the right part for the job.