2017-2019 GM 6.6L Duramax L5P Tier One 900HP Stage 2 Allison 1000 Transmission

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