DHD Dirty-Alli Hi-Performance 10L1000 Stage 2 Built Transmission | 2020+ GM 2500/3500HD

The DHD L5P Allison 10L1000 Built 10-Speed Stage 2 Transmission is designed for 2020–2025 GM trucks equipped with the 6.6L Duramax L5P and Allison 10L1000 automatic transmission. Built for higher horsepower diesel applications, this upgraded transmission features strengthened internal components and proprietary improvements to support engines producing up to approximately 600 horsepower.

Each transmission is assembled in a clean, controlled environment using a meticulous remanufacturing process. All components are hot tanked, ultrasonically cleaned, and thoroughly inspected before assembly to ensure quality and durability. During the build process, precise measurements, functional testing, and piston apply tests are performed to verify proper operation before the transmission leaves the bench.

The Stage 2 package incorporates increased clutch capacity, a DHD hard anodized F drum, and proprietary valve body modifications to improve clutch holding power and transmission performance. A Goerend triple-disc torque converter is included to enhance torque transfer and durability in higher output diesel applications. Additional new OEM components are installed throughout the transmission to ensure reliable operation and long service life.

• Vehicle Fitment: 2020–2025 GM 6.6L Duramax L5P
• Transmission Model: Allison 10L1000 10-Speed Automatic
• Power Rating: Up to approximately 600 horsepower
• Increased OE Clutch Capacity: Improved holding strength for higher power levels
• DHD Hard Anodized F Drum: Reinforced internal component for enhanced durability
• Goerend Triple Disc Torque Converter: Increased torque capacity and improved power transfer
• Valve Body Improvements: New valve body with proprietary DHD modifications
• New Electronics and Wiring: Ensures consistent transmission operation
• Solenoid Stabilization and Testing: Verified for proper functionality
• Deep Transmission Pan: Increased fluid capacity to assist with cooling
• New OEM Gaskets, Seals, and Torrington Bearings
• New OEM Sump Filter Included

Core Requirement: A rebuildable transmission core and torque converter are required. To receive full core credit, the returned core must be rebuildable with no case damage, catastrophic failure, or broken hard parts. The returned core must match the model and type of the transmission purchased. Electronic functionality is not required and the core may show signs of normal wear.

Note: Core charge and freight are additional. Transmission longevity depends on proper tuning, sufficient cooling, and responsible driving habits. Excessive temperatures and repeated shock loads can shorten transmission life.