Product description
Recommended to add transmission cooler & Billet Flexplate to order.
Sales Tech will call to verify build details.
Stage 3 Allison Transmission for Chevy & GMC Duramax Pickups
Tow-Ready. Track-Ready. Built for 900 HP.
The Stage 3 Allison transmission is designed for Duramax owners who expect uncompromising performance in every situation. Whether you’re hauling substantial weight or pushing your truck through high‑power passes at the track, this build delivers consistent strength, crisp shifting, and the durability needed for extreme applications. Rated for up to 900 horsepower, it’s the go‑to choice for serious performance enthusiasts.
Engineered for Extreme Strength and High Output
This transmission combines upgraded clutch systems, billet hard parts, and precision‑machined components to withstand intense power levels while maintaining smooth, predictable operation. Every part is selected to enhance durability and ensure efficient power transfer, giving your truck the capability to handle demanding towing and high‑RPM racing environments with confidence.
Premium Components for Maximum Reliability
Raybestos or ALTO G3 C‑3 & C‑4 Torque Kit with custom‑machined pressure plates for increased holding power
LML‑Style Pistons & Return Springs for improved performance under heavy load and high stress
Raybestos or ALTO G3 C‑1 & C‑2 Torque Kit to boost clutch capacity and heat resistance
Ratio Tek Pressure Upgrades for stronger hydraulic performance and consistent pressure control
Transgo Trim Valves to refine shift quality and stabilize internal pressures
New Torrington Bearings to reduce friction and extend component life
Randy’s Torque Converter with Billet Stator, available with custom stall options tailored for towing or racing setups
Billet Input Shaft for superior torque handling and long‑term durability
Billet C‑2 Hub engineered to withstand extreme power levels
Heavy‑Duty Cast Aluminum Deep Pan for increased fluid capacity and improved cooling
Why Choose Randy’s Stage 3 Allison?
Randy’s Transmissions is known for building high‑performance units that hold up under the toughest conditions. The Stage 3 Allison is no exception—each transmission is assembled with precision, tested extensively, and proven to perform in both towing and racing environments. We only release products that meet our highest standards, ensuring you get a transmission capable of handling real‑world abuse.
Driven by Experience and Continuous Development
Years of hands‑on testing, refinement, and innovation have shaped the Stage 3 Allison into a top‑tier performance transmission. Every component and calibration is the result of extensive research and real‑world validation. When you choose Randy’s, you’re investing in a transmission built from expertise, not guesswork.
1‑Year / 12,000‑Mile Warranty
Your Stage 3 Allison transmission is backed by a 1‑year, 12,000‑mile warranty, giving you confidence that your investment is protected. Whether you’re towing heavy equipment or pushing your Duramax to its limits at the track, you can count on dependable performance and support from a team committed to quality.