Description:
A Transmission Electronic Control Module (Transmission ECM or TCM) 24256861 is a specialized computer that manages and controls the automatic transmission system in a vehicle.

Part Number: 24256861
Condition: Remanufactured
Manufacture/Brand: Allison
Related Part Numbers: 24256670, 19431596, 19434406

Fits 24256861 For

Chevrolet Silverado: 2009, 2010, 2011, 2012, 2013, 2014, 2015
GMC Sierra 2500 HD: 2009, 2010, 2011, 2012, 2013, 2014, 2015
GMC Sierra 3500 HD: 2009, 2010, 2011, 2012, 2013, 2014, 2015

Model: T14 A50
Engine Size: 6.6L Duramax [LLY, LBZ, LMM]
Transmission: 6 Speed Transmission

Purpose of using 24256861:

  • Monitors vehicle sensors such as speed, engine load, throttle position, and temperature.

  • Controls shifting by deciding when to shift gears based on driving conditions and engine performance.

  • Regulates torque converter lockup for fuel efficiency and smooth driving.

  • Protects the transmission by preventing shifts that could cause damage.

  • Communicates with the Engine Control Module (ECM) and other vehicle systems to optimize overall performance.


Signs of a Bad Transmission Electronic Control Module (ECM) 24256861

  • Erratic or harsh shifting: Unusual gear changes or delays

  • Transmission slipping: Unexpected loss of power or acceleration

  • Failure to engage gears: Inability to shift into drive, reverse, etc.

  • Dashboard warning lights: Illumination of transmission or engine warning indicators

  • Diagnostic Trouble Codes (DTCs): Presence of fault codes related to transmission control