Restore Peak Performance to Your Allison Transmission
Is your 2001-2005 Silverado or Sierra HD truck suffering from harsh shifting, getting stuck in gear, or an illuminated check engine light? These are classic signs of a failing Transmission Control Module (TCM). The TCM is the electronic brain of your Allison transmission, and when it malfunctions, it can cripple your truck’s performance and reliability. This isn’t just an annoyance; it’s a critical failure that can leave you stranded. We offer a direct, reliable solution: a replacement TCM, part number 15768288, that arrives at your door fully programmed to your truck’s specific VIN.
From the Diagnostic Bay
I’ll never forget a customer who brought his ’04 Silverado 2500HD into my shop. He was a contractor who depended on his truck daily. It was stuck in “limp mode” (3rd gear only) and throwing a U0101 codeâLost Communication with TCM. He was worried about a costly transmission rebuild. After confirming power and ground at the TCM connector, it was clear the module itself had failed internally, a common issue on these workhorses due to heat and vibration. We swapped in a VIN-programmed module just like this one. In under 30 minutes, the truck was shifting perfectly, the codes were gone, and he was back on his way to the job site, having avoided thousands in unnecessary repairs at the dealership. This part is often the simple fix for what seems like a catastrophic problem.
Is Your Truck Showing These Symptoms?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, this module is the likely solution for your 2001-2005 Silverado 3500 TCM issues.
- â Abrupt, harsh, or delayed gear shifts
- â Vehicle entering “limp mode” (stuck in a single gear)
- â Flashing “Tow/Haul” light or gear indicator
- â “Service Engine Soon” or “Transmission Fault” message on the dash
- â Inaccurate speedometer readings
- â Common Diagnostic Trouble Codes (DTCs) such as P0700, P0751, P0842, or U0101 (No Communication with TCM)
A Straightforward Guide to Installation
One of the greatest benefits of this module is that it arrives ready to install, saving you a trip to the dealer for expensive programming. You can do this job with basic hand tools.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the TCM: On these GM HD trucks, the TCM is conveniently located on the driver’s side (LH) of the radiator fan shroud. You can’t miss it.
- Disconnect the Module: Carefully unplug the large electrical connectors from the old TCM. There are release tabs you’ll need to press.
- Remove the Old Unit: Unbolt the old module from its mounting bracket on the fan shroud.
- Install the New TCM: Mount your new, pre-programmed TCM onto the bracket and securely fasten it.
- Reconnect Everything: Plug the electrical connectors firmly into the new module. You should hear or feel a click. Reconnect your battery terminal.
- Final Check: Start the vehicle and allow it to idle. Cycle through the gears (P-R-N-D) and take it for a test drive to confirm smooth shifting has been restored.
Guaranteed Fitment for Your GM HD Truck
This module is a direct-fit replacement for several service numbers and is specifically designed for heavy-duty trucks equipped with the 5-speed Allison automatic transmission (RPO Code M74). Please verify your vehicle is on this list:
Transmission Option: 5-Speed Allison Automatic (M74)
GMC Sierra 2500 HD & 3500 (2001-2005)
Transmission Option: 5-Speed Allison Automatic (M74)
This part is a direct replacement for the following service numbers (SERV NO): 15768288, 15071240, 15163072, 15163073, 15169833, 15169834, 15169835, 15183963, 15187103, 15187104, 29537441, 09385220, 09387820.
Frequently Asked Questions
Do I need to program this module?
Do I need to program this module?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s 17-digit VIN during or after checkout, and we will flash the module with the latest GM-certified software for your specific truck. It arrives ready for plug-and-play installation.
Where is the TCM located on my 2004 Silverado 3500?
The Transmission Control Module is mounted directly to the driver’s side of the radiator fan shroud in the engine bay. It’s easily accessible for a quick replacement.
What happens if I don’t provide my VIN?
Providing your VIN is essential for the programming service. We cannot ship the module until we receive your VIN, as the programming ensures the TCM communicates correctly with your truck’s engine and other systems. This step is what makes the installation so simple.
Will this fix my truck’s limp mode?
If the limp mode is being caused by a faulty or non-communicating TCM (often indicated by codes like U0101), then yes, replacing it with this correctly programmed module is the definitive fix. It restores the communication link required for normal transmission operation.
Is this a genuine GM part?
This is a high-quality replacement module that is programmed using official GM software updates. It is designed to meet or exceed original equipment specifications for function and reliability, ensuring a lasting repair for your vehicle.