Restore Peak Performance to Your Workhorse Van
If your 2006-2014 GMC Savana 3500 is your mobile office or your primary work tool, you can’t afford downtime caused by transmission problems. A faulty Transmission Control Module (TCM) is often the hidden culprit behind erratic shifting, poor fuel economy, and that dreaded check engine light. Over my 20 years in diagnostics, I’ve seen countless work vans sidelined by what seems like a major transmission failure, when the real issue was a failing electronic module. This T42 TCM, part number 24235340, is the definitive, hassle-free solution to get your van running reliably again.
We take the guesswork and extra cost out of the repair. Each module is expertly programmed to your van’s specific Vehicle Identification Number (VIN) before it ships. This means no expensive trips to the dealership for programming—it’s a true plug-and-play fix. This is the same process we use in our own shop to guarantee a seamless repair, restoring the precise shift logic your GM 4-speed automatic (like the 4L80E in your Savana) was designed with.
A Technician’s Notebook: The Intermittent Shifting Nightmare
I once had a fleet customer with a 2011 Savana 3500 that had the most frustrating issue. The driver would complain of harsh 1-2 shifts and occasionally getting stuck in 3rd gear (limp mode), but only on hot days after about an hour of city driving. We checked fluid levels, scanned for codes (sometimes a generic P0700, sometimes nothing), and couldn’t find a mechanical fault. The problem was heat soak affecting the original TCM’s internal circuits. After swapping in a pre-programmed T42 module, the problem vanished instantly. It’s a classic example of how a failing TCM can mimic a more serious internal transmission problem, and why a quality replacement is key.
Is Your Savana Van Showing These Red Flags?
A failing TCM doesn’t always mean a complete transmission shutdown. It often starts with subtle signs. If you’re experiencing any of the following, your TCM is the likely cause:
- ✔ Unpredictable or harsh shifting, especially when the engine is warm.
- ✔ The transmission feels like it’s slipping or hesitating between gears.
- ✔ Your van is stuck in one gear (often called “limp mode”) and won’t shift up or down.
- ✔ The Check Engine Light or a specific transmission warning light is illuminated on your dash. Common trouble codes include P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (e.g., P0751, P0756).
- ✔ A noticeable drop in fuel efficiency as the transmission isn’t shifting at the optimal points.
- ✔ Complete loss of communication with the transmission, preventing it from engaging at all.
A Straightforward Guide to Your 2006-2014 Savana 3500 TCM Installation
You don’t need to be a master mechanic to perform this replacement. The process is straightforward and can be completed in under 30 minutes with basic hand tools.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on any electronic components.
- Locate the Module: In most 2006-2014 Savana and Express vans, the TCM is located in the engine compartment on the right-hand (passenger) side.
- Disconnect and Remove: Carefully unplug the electrical connectors. Note the locking tabs to avoid damage. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt your new, VIN-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock in.
- 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 lingering diagnostic trouble codes (DTCs) from the vehicle’s memory.
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for part number 24235340 and is interchangeable with other service numbers including 24252114, 24234503, 24230461, and more. While this page focuses on the Savana 3500, it also fits a wide range of other GM vehicles:
SAVANA 3500 VAN 06-14 Transmission; (RH engine compartment)
EXPRESS 3500 VAN 06-14 Transmission; (RH engine compartment)
SAVANA 2500 VAN 06-14 Transmission; (RH engine compartment)
EXPRESS 2500 VAN 06-14 Transmission; (RH engine compartment)
SAVANA 1500 VAN 06-14 Transmission; (RH engine compartment)
EXPRESS 1500 VAN 06-14 Transmission; (RH engine compartment)
SILVERADO 1500 PICKUP 07-13 Transmission; (next to battery)
SIERRA 1500 PICKUP 07-13 Transmission; (next to battery)
TAHOE 07-09 Transmission; (next to battery)
YUKON 07-09 Transmission; (next to battery)
SUBURBAN 1500 07-08 Transmission; (next to battery)
YUKON XL 1500 07-08 Transmission; (next to battery)
AVALANCHE 1500 07-08 Transmission; (next to battery)
COLORADO 08-12 Transmission; (RH rear engine compartment)
CANYON 08-12 Transmission; (RH rear engine compartment)
HUMMER H3 08-10 Transmission; (RH rear engine compartment)
IMPALA 06-11 Transmission; (lower air cleaner housing)
MONTE CARLO 06-07 Transmission; (lower air cleaner housing)
LACROSSE 06-09 Transmission; (lower air cleaner housing)
ALLURE 06-09 Transmission; (lower air cleaner housing)
GRAND PRIX 06-08 Transmission; (lower air cleaner housing)
COBALT 06-10 Transmission; (LH strut tower)
G5 07-10 Transmission; (LH strut tower)
HHR 06-11 Transmission; (LH engine compartment)
…and many more GM models from 2006-2014.
Frequently Asked Questions
What exactly does this Transmission Control Module do?
The TCM acts as the ‘brain’ for your automatic transmission. It processes data from vehicle sensors to control shift timing, hydraulic pressure, and torque converter lockup, ensuring smooth and efficient operation.
Is this part really plug-and-play?
Yes. We program the module to your vehicle’s VIN before shipping. This ensures it has the correct software and calibrations for your specific Savana 3500, eliminating the need for a dealership visit for programming.
Do I need to send my old TCM back?
No. There is no core charge for this part. You can keep or dispose of your old module, making the repair process simpler and faster for you.
Can I install this myself if I’m a DIYer?
Absolutely. For most models, including the Savana van, the TCM is located in an accessible part of the engine bay. With basic hand tools and our installation guide, this is a very manageable job for a DIY enthusiast.
What happens if I ignore a failing TCM?
Ignoring the symptoms can lead to more severe problems. Poor shifting can cause premature wear on clutches and bands inside the transmission, potentially leading to a much more expensive mechanical failure down the road. It’s also a safety issue if the van fails to accelerate or shift correctly in traffic.