ATS 309-822-4290 Stage 2 Allison LCT1000 Crate Transmission | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY 2WD

Features:

• Fits 2004.5–2005 Silverado and Sierra 2WD trucks
• Built for 6.6L Duramax LLY engine applications
• Includes ATS Stage 2 LCT1000 transmission
• Comes with ATS Five Star torque converter
• Deep transmission pan increases fluid and cooling capacity
• ATS Co-Pilot controller improves shift logic and pressure
• No tuning or calibration required after installation
• Fully assembled and ready for bolt-in install
• Great for towing and daily performance use
• Reinforced internals for increased torque handling
• Designed for long-term durability under heavy load
• $500 shipping surcharge added at checkout

Make Your LLY Run Stronger With A Transmission That Keeps Up

If your 2004.5 to 2005 Duramax LLY is still getting worked hard but your factory transmission is falling behind, this is the upgrade that changes everything. The ATS Stage 2 Allison LCT1000 Crate Transmission is built to handle more power, deliver smoother shifts, and give your truck the reliable performance it deserves. Whether you’re towing long distance, hauling heavy gear, or just want more confidence every time you mash the throttle, this package steps up where your stock setup starts to fade. With the included Five Star torque converter, you get tighter lockup and more efficient torque transfer, while the deep pan keeps fluid temperatures in check during demanding runs. Add in the ATS Co-Pilot controller, and your shift points become crisper and more intelligent, without needing a custom tune or reflash. It all comes pre-assembled, ready to drop in, so you can spend less time wrenching and more time getting work done. This isn’t just a replacement, it’s a transmission that matches the muscle of your Duramax.

Built For Durability Heat Control And Confident Shifting

The ATS 309-822-4290 Stage 2 Allison LCT1000 Transmission Package is specifically engineered for 2004.5–2005 GM 2500HD and 3500HD 2WD trucks equipped with the 6.6L Duramax LLY. This transmission package includes a fully upgraded LCT1000, rebuilt by ATS with enhanced clutches, improved valve body calibration, and stronger internal components to handle increased horsepower and load stress. It’s paired with the ATS Five Star torque converter, which delivers firm lockup, reduced slippage, and better torque multiplication, especially useful when towing or accelerating under load. The deep transmission pan adds fluid capacity for improved cooling and long-haul protection, reducing wear and thermal breakdown over time. The system also includes the ATS Co-Pilot transmission controller, which automatically adjusts line pressure and shift strategy based on real-time driving conditions. No tuning or programming is needed, making installation straightforward for performance shops and experienced DIYers alike. This package ships fully assembled, offering a direct-fit solution for drivers who demand better shift control, cooler temps, and long-term reliability from their transmission. It’s the right match for LLY owners pushing their trucks to do more.

Fits: 2004.5, 2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY 2WD

Notes:

• Fits 2004.5–2005 Silverado and Sierra 2500HD/3500HD 2WD models
• Built specifically for the 6.6L Duramax LLY engine
• Includes a fully upgraded Stage 2 LCT1000 transmission
• Comes with ATS Five Star torque converter for better lockup and efficiency
• Includes deep transmission pan for improved fluid capacity and cooling
• ATS Co-Pilot controller enhances shift control and line pressure
• No tuning or aftermarket reprogramming is needed for installation
• Ships fully assembled for direct bolt-in replacement
• Ideal for towing, heavy-duty use, and performance builds
• Professional installation is highly recommended for best results
• $500 shipping surcharge will be applied during checkout