The Diamond T TCM for Chevy/GMC (2006-09) 2500/3500 with Allison 6-speed (T14/T14A & A40) is a remanufactured, upgraded transmission control module built for 6.6L Duramax LBZ and LMM trucks that work, tow, and tow heavy. Designed for MW7 Allison 6-speed applications that use the LH fan shroud layout, this unit matches common OE Service IDs such as 15117030, 24256864, 25798264, and 25982143 when selected by the correct model year and options.
Each Diamond T TCM is completely overhauled, inspected, and tested to exceed OEM standards, helping restore proper shift timing, torque converter control, and overall Allison 6-speed behavior. When you provide your VIN at order, the module is programmed to the latest manufacturer calibration so it arrives ready for plug and play installation—no dealer trip or long downtime required.
Compatible with both classic (creased door skin) and new body style (smooth door skin) 2007 Silverado and Sierra 2500/3500 trucks, this TCM is built to live behind tuned Duramax power, heavy trailers, and daily work use. Backed by a 1 year warranty and wearing the Diamond T name, it delivers the durability and drivability serious diesel owners expect—American Made, Because It Matters.
