Tier One Transmissions
2017-2019 GM 6.6L Duramax L5P Tier One 900HP Stage 2 Allison 1000 Transmission
2017-2019 GM 6.6L Duramax L5P Tier One 900HP Stage 2 Allison 1000 Transmission
SKU:TODT1-A1-ST2-1719-X-2WD
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Tier One Stage 2 Allison 1000 Transmission for 2017-2019 GM 2500/3500 6.6L L5P Duramax
The Tier One Stage 2 Allison 1000 Transmission is built to handle extreme power levels, heavy towing, off-roading, sled pulls, and racing. Designed for 2017-2019 GM 2500 & 3500 6.6L L5P Duramax trucks, this complete drop-in transmission supports up to 900 horsepower from aggressive Duramax tuning, bigger turbos, oversized injectors, and exhaust upgrades.
Key Features:
- Billet triple-disc torque converter
- Billet input shaft
- Billet C2 clutch hub
- High-pressure valve body with RatioTek kit
- Performance overhaul kit with additional clutches (C1, C2, C3, C4)
- Deep transmission pan
- New PCS solenoids and internal wiring harness
- New switch manifold
- Billet PTO cover with C3 oiler notch
- New transmission filter
- Black powder-coated finish
Benefits:
- Fixes common Allison transmission issues
- Handles extreme power and torque for sled pull, drag racing, off-road, and towing applications
- Valve bodies are leak-checked and dyno-tested before installation
- Shifts slightly firmer than stock for performance
- 2-Year unlimited mileage warranty
Specifications:
- Vehicle Fitment: 2017-2019 GM Silverado or Sierra 2500/3500 with 6.6L Duramax L5P
- Transmission Type: Allison 1000
- Power Rating: Up to 900 horsepower
- Torque Converter: Billet triple-disc
- Input Shaft: Billet Steel
- Intermediate & Output Shaft: OEM
- Valve Body: High-pressure with RatioTek kit
- Clutch Hub: Billet Steel
- Clutches: SPZ/Raybestos, increased C1-C4 count
- Transmission Pan: Deep with increased capacity
- Geartrain: OEM/Machined P1 Sun Gear
- PTO Cover: Billet Aluminum with "Tier One" lettering & C3 oiler upgrade
Additional Notes:
- For 2017-2019 GM Duramax L5P 2500 & 3500 only
- Requires a 300-mile break-in and a 100-mile transmission relearn
- Freight shipping required; inspect before signing Bill of Lading
- $2,500 core charge applies, refundable once stock transmission is returned and inspected
- Recommended gearing by tire size:
- 35": 3.73 or higher
- 37": 4.10 or higher
- 38"+: 4.56 or higher
