ATS 309-864-4272 Stage 6 Allison LCT1000 Crate Transmission | 2003-2004 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7 4WD

Features:

• Fits 2003–early 2004 LB7 Duramax 4WD trucks
• Includes billet input, output, and intermediate shafts
• Features ATS Five Star torque converter
• Deep pan increases cooling and fluid capacity
• Co-Pilot controller improves shifting and pressure control
• Billet P2 carrier and billet C2 hub included
• Modified P1 sun gear adds internal strength
• Built for towing and high-horsepower applications
• Fully assembled crate transmission for easy install
• Optimized for durability under heavy load
• Factory fitment with enhanced performance upgrades
• $500 shipping surcharge applies at checkout

Let Your LB7 Pull Like It Was Born To

If you’re still putting stock power through an overworked transmission in your 2003–early 2004 LB7 Duramax, you’re not getting the full performance your truck was built for. The ATS Stage 6 Allison LCT1000 Crate Transmission is your answer to better towing, smoother shifting, and long-term durability without compromise. Whether you’re hauling trailers, running a tune, or just want peace of mind on long drives, this transmission is made to deliver. With the ATS Five Star torque converter, deep transmission pan, and Co-Pilot controller working together, your shifts become more responsive and consistent even under load. It’s fully assembled and built to handle heavy-duty use right out of the box, saving you time and keeping your build moving forward. Every component in this package is designed to hold up under pressure, so your truck performs like it should without the drama. If your LB7 works hard, this transmission makes sure it stays ready for more.

Internal Upgrades Designed For Reliable Power Delivery

The ATS 309-864-4272 Stage 6 Allison Transmission is built specifically for 2003–early 2004 GM Silverado and Sierra HD trucks with the 6.6L LB7 Duramax and 4WD configuration. Inside the case, billet input, output, and intermediate shafts replace weaker factory components, providing a stronger backbone for tuned and towing-focused builds. The transmission also features a billet P2 carrier and billet C2 hub, reinforced with a modified P1 sun gear to improve gear set durability and withstand high torque demands. The Five Star torque converter ensures efficient torque multiplication while minimizing slippage, making a big difference when towing or under throttle. For added control, the ATS Co-Pilot transmission controller dynamically manages line pressure and shift timing, protecting clutches and improving drivability in both stock and performance setups. A deep pan increases fluid capacity, helping reduce heat and extend transmission life under strain. This crate transmission ships fully assembled, offering a drop-in performance upgrade with factory fitment. It’s a complete system engineered for reliability, strength, and smarter control across the board.

Fits: 2003, 2004 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7 4WD

Notes:

• Designed specifically for 2003–early 2004 6.6L LB7 Duramax engines
• Fits GM Silverado and Sierra 2500HD/3500HD 4WD configurations
• Transmission is shipped fully assembled as a crate unit
• Includes ATS Five Star torque converter and deep transmission pan
• ATS Co-Pilot transmission controller enhances shift control and longevity
• Billet internal components are engineered to handle high torque loads
• Ideal for towing, performance upgrades, and heavy-duty applications
• Factory fitment ensures a direct-replacement install
• Built to withstand increased power from tuned or modified engines
• A $500 shipping surcharge will be added at checkout