Features:
- Includes Five Star torque converter
- Deep transmission pan improves cooling
- Billet input shaft for added durability
- Designed for high-performance applications
- Co-Pilot controller optimizes shift strategy
- Supports heavy towing and horsepower upgrades
- Fits 2004.5–2005 LLY Duramax 4WD trucks
- Complete crate transmission solution
- Enhanced clutch engagement and holding power
- Improves torque handling and reliability
- Backed by ATS performance engineering
- Perfect for daily driving or towing builds
Built to Handle What the Factory Can’t
When you're pushing the limits of your 2004.5–2005 LLY Duramax, the stock transmission just isn't up to the task. That’s where the ATS 309-834-4290 Stage 3 Allison LCT1000 Crate Transmission steps in. This complete upgrade package is engineered from the ground up for 4WD Silverado and Sierra 2500HD/3500HD trucks that demand more from every mile. Whether you're towing heavy loads, stacking power mods, or doing both, this transmission offers the performance, durability, and control needed to keep up. Included in the package is ATS's proven Five Star torque converter, billet input shaft, deep transmission pan, and the Co-Pilot transmission controller—all working together to deliver improved shift quality, torque handling, and thermal management.
Purpose-Built Components, Seamless Integration
What sets this package apart is its focus on real-world performance. The billet input shaft provides the strength needed to resist twisting under heavy torque, while the deep transmission pan boosts fluid capacity and cooling. The ATS Co-Pilot controller ensures shift points are optimized for both power delivery and drivability—no matter the conditions. And with the Five Star torque converter maximizing torque multiplication at low RPM, you’ll notice better acceleration and responsiveness under load. Whether you're building a reliable tow rig or simply looking to eliminate the weak link in your drivetrain, this Stage 3 crate transmission delivers peace of mind and serious performance without compromising daily usability.
Fits: 2004.5, 2005 GM 2500HD/3500HD 6.6L Duramax LLY 4WD
Includes:
- ATS 4WD 2004.5-2005 Allison LCT1000 Performance Transmission
- ATS Allison LCT1000 Five Star Torque Converter (302-950-4248)
- ATS Allison LCT1000 Deep Transmission Pan (301-900-4248)
- ATS Co-Pilot Transmission Controller (601-924-4248)
- Billet Input Shaft
Note: $500 Shipping surcharge will be added at checkout
ATS 309-834-4290 Stage 3 Allison LCT1000 Crate Transmission | 2004.5-2005 GM 2500HD/3500HD 6.6L Duramax LLY 4WD
ATS Diesel Performance
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$7,331.95
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ATS Diesel Performance
ATS 309-834-4290 Stage 3 Allison LCT1000 Crate Transmission | 2004.5-2005 GM 2500HD/3500HD 6.6L Duramax LLY 4WD
- SKU:
- ATS309-834-4290
- UPC:

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ATS Diesel Performance
ATS 309-832-4290 Stage 3 Allison LCT1000 Crate Transmission | 2004.5-2005 GM 2500HD/3500HD 6.6L Duramax LLY 2WD
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ATS Diesel Performance
ATS 309-814-4290 Stage 1 Allison LCT1000 Crate Transmission | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY 4WD
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ATS 309-844-4290 Stage 4 Allison LCT1000 Crate Transmission | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY 4WD
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ATS 309-824-4290 Stage 2 Allison LCT1000 Crate Transmission | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY 4WD
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$6,538.95
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