This Synapse Transmission Control Module (TCM) is a fully remanufactured, stock‑calibration replacement for 2011–2015 GM 6.6L Duramax trucks equipped with the Allison automatic transmission, built to restore factory shift quality while remaining 50‑state legal for use in California and other emissions‑regulated states.
The Synapse S72‑1G01115GD Transmission Control Module is a direct‑fit, remanufactured Allison TCM for 2011–2015 Chevrolet and GMC 6.6L LML Duramax trucks, programmed to your VIN for plug‑and‑play installation with no dealer flashing required. This unit is a stock‑replacement controller (no performance tuning) that meets California emissions requirements, making it ideal when your original A50/T14 TCM has failed or is intermittently acting up.
Application: 2011–2015 Chevrolet and GMC 6.6L LML Duramax equipped with Allison 1000 automatic transmission
Typical trucks covered:
2011–2015 GMC Sierra 2500HD / 3500HD 6.6L Duramax
2011–2015 Chevrolet Silverado 2500HD / 3500HD 6.6L Duramax
Service type: Exchange remanufactured TCM (you receive a rebuilt unit and return your original core)
Configuration: Stock calibration only – no performance or shift‑strategy tuning is included with this part; it is a factory‑style replacement unit
Emissions status: California‑legal, suitable for use in emissions‑controlled vehicles where modified transmission tuning is restricted
Brand: Synapse
SKU / Item #: S72‑1G01115GD
Condition: New, fully remanufactured control module
OEM cross‑reference (examples): A5100S92, A5100NC6, 19431596, 24256861, 24259874, 24257038, 24266710
Weight: 3 lb; package dimensions approx. 5 x 10 x 10 in
Vehicle electrical system: Designed for 12‑volt automotive applications (operates within factory GM voltage range)
Location: 100% USA‑based remanufacture and test facility for the core electronics
Corrects many common Allison TCM failures such as erratic shifting, limp‑mode, or loss of gear selection while preserving the factory shift strategy required for emissions compliance.
Stock‑calibration programming maintains OEM line pressures, torque‑converter behavior, and shift timing to prevent drivability issues or emissions test failures in states like California.
Each exchange TCM is pre‑programmed to your truck’s specific VIN before it ships, so no dealer‑level flashing or additional programming is needed in most applications.
Direct‑fit connectors and factory‑style mounting points allow a straightforward installation using basic hand tools, typically in well under an hour for most experienced owners or shops.
Properly functioning TCM logic is critical to controlling clutch apply pressure, torque‑converter lockup, and converter slip; a failed module can quickly damage an otherwise healthy Allison transmission.
Replacing a failing A50/T14 module early can prevent harsh engagement, excessive converter slip, and overheating that lead to costly internal transmission repairs.
The exchange unit is fully disassembled, inspected, and rebuilt, with known‑failure components on the circuit board replaced or upgraded where appropriate.
Each TCM is tested on specialized equipment to confirm proper communication, sensor input processing, and output driver performance before shipment.
This listing is specifically for a stock‑replacement TCM; it does not include PPEI or any other custom transmission tuning package.
By preserving factory-correct shift logic and torque‑management strategy, this controller remains suitable for use on emissions‑controlled and California‑registered vehicles where performance tuning may not be legal.
This product is sold as an exchange service: you receive a remanufactured TCM and return your original module (core).
Place order:
Select the 2011–2015 Duramax Allison TCM Exchange on norcaldieselperformance.com and complete checkout with accurate vehicle info and VIN.
Programming & shipment:
Your exchange TCM is programmed to your VIN and shipped, usually via ground service with optional expedited methods available at checkout.
Install the exchange TCM:
Disconnect the batteries, remove your original TCM, install the remanufactured unit, and reconnect batteries; most trucks will recognize the module immediately.
Return your core:
Package your original A50/T14 TCM securely with several inches of padding on all sides and send it back following the instructions on your NorCal Diesel Performance order.
Your returned TCM generally must meet the following conditions to be an acceptable core:
No obvious fire damage.
No heavy flood or corrosion damage.
Must be an A50 or T14‑style Allison TCM for 2009–2015 applications (casting and connector style must match).
Housing and circuit board must be complete, with no missing sections or broken‑off corners.
Previous repair attempts are usually acceptable as long as the board and components are intact and not burned beyond repair.
Core‑charge and return‑window specifics are governed by NorCal Diesel Performance’s current policies; review your cart and confirmation email for exact terms and any core‑charge amounts or deadlines that may apply.
A failing A50/T14 TCM on 2011–2015 Duramax trucks can cause a variety of driveability issues. The Synapse exchange unit is designed to address failures attributable to the TCM electronics and solder joints.
Sudden limp‑mode with limited gear availability (e.g., locked in 3rd or 5th gear) even though the transmission itself is mechanically sound.
Harsh or erratic shifts, delayed upshifts, flare between gears, or refusal to downshift under load.
Intermittent “Service Trailer Brake System” or “Service Transmission” messages coinciding with loss of gear indication in the cluster.
No‑crank or no‑start condition on some trucks when the TCM cannot communicate with the ECM over the high‑speed CAN bus.
Loss of manual gear selection (TapShift / manual mode in M range) while PRNDL still appears normal.
Exact codes will vary by failure mode, but common TCM‑related DTCs on LML trucks include:
U0101 – Lost Communication with TCM (set in the ECM)
P0700 – Transmission Control System Malfunction (general transmission fault flag)
P0711 / P0713 – Transmission Fluid Temperature Sensor Performance / High Input (if internal sensor circuit is affected)
P0729–P0736 – Gear ratio error codes if the TCM can no longer accurately control or monitor shifts.
If codes point to internal transmission slip or hard‑part damage rather than a communication or logic fault, the TCM may not be the root cause; thorough diagnosis is recommended before ordering.
Skill level: Suitable for experienced DIY owners comfortable working around vehicle electrical connectors and modules, or any professional shop familiar with GM Duramax trucks.
Basic steps:
Disconnect both batteries
Access and unbolt the original TCM (location varies by model year but is typically near the radiator support or driver‑side engine bay)
Transfer any mounting hardware
Plug in the remanufactured unit and reinstall
Reconnect batteries and verify operation and shift feel on a test drive
Programming: Unit is pre‑programmed to your VIN for plug‑and‑play operation; no separate dealer programming is normally required.
If the truck still exhibits the same symptoms after installing the exchange TCM, further diagnosis of wiring, grounds, CAN harness, and internal transmission issues is recommended.
Duration: Up to 2‑year warranty period on the remanufactured TCM from date of purchase.
What is covered:
Defects in materials and workmanship of the remanufactured TCM under normal use.
Failures traced to internal electronic component issues originally addressed during the reman process.
Remedy:
At Synapse's discretion, the unit may be repaired again, replaced with another remanufactured module, or refunded in accordance with current manufacturers policies.
Damage from improper installation, wiring faults, shorted harnesses, or other external vehicle issues.
Damage from water intrusion, fire, collision, or obvious abuse.
Failures caused by unrelated powertrain or drivetrain problems (e.g., failing transmission hard parts) rather than TCM electronics.
Labor charges, towing, rental vehicles, or incidental and consequential damages.
Always refer to the NorCal Diesel Performance checkout page and store policies for the live, warranty language associated with this product.
No. This listing is strictly for a stock replacement Allison TCM and does not include PPEI or any other performance‑oriented transmission tuning. If you are looking for PPEI‑tuned Allison control, use this part number specifically packaged with PPEI custom tuning.
Yes. Because this unit retains stock‑style transmission calibration with no custom torque‑management or shift‑strategy changes, it is suitable for use in emissions‑controlled states, including California, as a direct‑replacement control module. Always verify local regulations for any additional requirements on modified or heavily upgraded trucks.
In most cases, no. The exchange TCM is pre‑programmed for your truck’s VIN, so once installed it should communicate with the ECM and function like a factory unit without a dealer flash. If the truck has extensive previous custom tuning, extra steps or re‑syncing may occasionally be required by your tuning provider.
This SKU is designed to replace failed stock‑type A50/T14 controllers and does not include custom tuning. Trucks that rely on custom transmission files will either need that tune re‑applied by the original tuning vendor after installation or choose the PPE Tuning option here.
We recommend your core is returned within 30 days for full core credit. If you have a special situation just give us a call. 888-290-382
Lightly damaged or previously repaired modules are usually acceptable, but units with severe fire or flood damage, missing connectors, or broken boards may not qualify as a rebuildable core. If there is any doubt, contact NorCal Diesel Performance before ordering to discuss your specific TCM condition.
If those symptoms are caused by a failing TCM—such as corrupted shift logic, erratic solenoid control, or communication dropouts—replacing the module can restore normal operation. If the underlying problem is worn clutch packs, a failing torque converter, or mechanical damage, those issues will remain and require transmission repair.
Yes, many owners install this TCM in their driveway with basic tools, following standard safety procedures like disconnecting the batteries and avoiding static discharge to the module. Professional installation is recommended if you are not comfortable working with vehicle electronics or diagnosing CAN‑bus and wiring issues.
For LML owners experiencing limp‑mode, shift issues, or TCM communication codes, this Synapse 2011–2015 Duramax Allison TCM Exchange offers a VIN‑programmed, California‑legal, stock‑calibration replacement to get your truck reliably back on the road.
Total Reviews (0)You must login to post a review.
Write the First Review!