ATS TCM Upgrade, A40 / A50 to T87A, Early 2015 GM 6.6L Duramax

$4,062.59 CAD

Ships within 24-48 hours. Pickup available upon request.
SKU: 601-940-4416-FSMF Category:

ATS TCM Upgrade, A40 / A50 to T87A. Fitment: 2011- Early 2015 GM 6.6L Duramax. The A40 and A50 TCM that is used to control the Allison 6-speed automatic transmission is the weak link of the Allison transmission.

This is due to delicate thin wires inside the TCM that contact one another overtime and short-out the entire module. In 2022, Allison sent out a letter (SIL 15-1K2K-22) announcing the discontinuation of support for the A50 and A40.

This effectively left over 10,000 Duramax owners out of their trucks. So we got to work developing a solution utilizing our Translator technology found in the ATS Allison Conversion to help get these trucks back on the road, shifting and holding power even better than before, ASAP!

The A50 and A40 TCM have been used in all GM Duramax/Allison Diesel Trucks produced from 2006 to 2017. ATS is excited to release the new GM Allison T87A upgraded TCM module. The upgraded TCM comes in an assembly including our Translator module that also has our Co-Pilot transmission functions built in.


  • Works with stock or modified trucks.
  • Controls and increases line pressure.
  • Direct replacement, no permanent modifications required - plug and play OEM quality harness and module.
  • Found on the current 2023 Duramax, the T87a TCM has a much faster processor than the A50 and that equates to better shift quality, faster shifting and overall improved drivability.
  • Direct Replacement for AC Delco: TCM 24256861 25978353 15117030


  • New T87a TCM that is unlocked and has a custom ATS calibration pre-installed that optimizes the performance of the Allison transmission.
  • New Translator module that has the Co-Pilot transmission pressure function enhancements built in. The Co-Pilot functionality allows the factory Allison transmission to handle higher power levels and much better durability.
  • Mounting Bracket
  • Wiring Harness

Additional information

Weight 7.00 lbs
Dimensions 17.00 x 13.00 x 7.00 in
Country of Origin


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Warranty 5-Year/500,000 Mile Limited Warranty


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