Precision Shift Logic for Your Allison Transmission
Maintain the pulling power and reliability of your Silverado or Sierra HD with a factory-calibrated Allison 6-Speed TCM (24256864). Designed specifically for the A50/T14 logic systems, this module manages shift timing, torque converter lockup, and line pressure to protect your heavy-duty transmission under load.
Built for Heavy Duty Performance
- Optimized Calibrations: Flashed with the latest GM/Allison software updates for improved shift feel and durability.
- Duramax Compatibility: Engineered for the LBZ and LMM Duramax platforms (2006-2009).
- Direct Fit: Replaces common failed part numbers including 24238618, 24242391, and 24256864.
- Simplified Service: Arrives pre-programmed; simply install it and perform a ‘Fast Learn’ or drive through a few shift cycles for adaptation.
| Years | Model | Engine |
|---|---|---|
| 2006-2009 | Silverado 2500HD/3500HD | 6.6L Duramax Diesel |
| 2006-2009 | Sierra 2500HD/3500HD | 6.6L Duramax Diesel |
| 2006-2009 | Kodiak/Topkick C4500-C5500 | 6.6L Duramax Diesel |
Frequently Asked Questions
Is this a new or remanufactured unit?
This is a high-quality, tested/programmed OEM module guaranteed to function like new.
Will this widen my gear ratios?
No, this TCM restores factory performance based on your vehicle’s specific Allison transmission configuration.
Does it require a core return?
No core return is required for this product.
