Stage 1 Allison 1000 Transmission for Chevy & GMC Duramax Pickups

When it comes to towing heavy loads or adding a bit of extra power to your Chevy or GMC Duramax, the Allison 1000 transmission is a trusted workhorse. Randy’s Stage 1 Allison 1000 upgrade takes this already robust transmission and refines it for even better performance, durability, and reliability, making it the ultimate choice for any truck pushing up to 500 horsepower.

The Perfect Transmission for Towing and Mild Performance Enhancements

Designed for the truck owner who needs their vehicle to handle the daily grind, this Stage 1 Allison 1000 transmission ensures your Duramax has the reliable holding power needed to handle up to 500 HP. Whether you're hauling a heavy trailer up a steep mountain pass or looking for a smoother, more efficient power delivery for your day-to-day drives, this transmission upgrade is built to deliver.

Key Features & Components

Our Stage 1 Allison 1000 transmission kit is loaded with high-quality components designed to maximize performance and longevity. Here's what you can expect:

Raybestos or ALTO G3 C-3 and C-4 Packs with Additional Clutch Count: These clutches provide superior holding power, ensuring your transmission can handle the extra torque without slipping, even under heavy loads.
Randy’s Billet Torque Converter: Our built-in-house billet torque converter that enhances lock-up efficiency and torque transfer for smoother acceleration and increased durability.
Modified Lock-Up Valve: Optimized to enhance performance in towing and daily driving, ensuring better engagement and torque transfer.
Transgo Trim Valves: Improves fluid pressure regulation, reducing internal wear and extending the life of your transmission.
New Bonded Pistons: Improves overall durability and reliability, ensuring smooth shifting and efficient power transfer.
Raybestos or ALTO G3 C-1 and C-2 Clutches: High-performance clutches that provide superior durability and heat resistance.
New Bearings:We replace all the bearings to guarantee a smooth, reliable operation, reducing friction and wear.

Why Choose Randy's Stage 1 Allison 1000?

At Randy’s, we understand that when you're towing, working, or playing with your Duramax, reliability is key. That’s why we’ve developed the Stage 1 Allison 1000 transmission to be the perfect upgrade for truck owners who want peace of mind on the road, whether you're cruising on the highway or pulling a fifth wheel up a steep incline.

This transmission is designed for those who need their truck to hold a bit more power. With improved clutch packs and billet components, our Stage 1 transmission is engineered to handle up to 500 horsepower, keeping your Duramax running strong for years to come.

Built for Durability, Tested for Excellence

Every transmission we build is tested rigorously, ensuring it can stand up to the demands of real-world use. Whether you're towing, hauling, or just driving around town, Randy's Stage 1 Allison 1000 transmission is built to go the distance.

Buy Now, Pay Later

We know that upgrading your transmission is a big investment and paying all at once can be tough. That’s why we’ve teamed up with Affirm to make it easier for you. With our financing options, you can enjoy the benefits of a top-quality transmission without the stress of a hefty upfront payment. Available exclusively online, just choose Affirm at checkout and spread your payments out over time. Get the performance you need today, and pay at a pace that fits your budget.

2 Year / Unlimited Mile Warranty

When you choose Randy’s Stage 1 Allison Transmission, you’re backed by confidence and reliability. We stand behind our product with a 2-year, unlimited mile warranty, ensuring your transmission performs at its best—no matter how hard you push it. Whether you’re towing heavy loads or running down the road, rest easy knowing that our warranty has you covered. We’re committed to providing long-term durability and peace of mind with every build.

Refresh Program

Refresh Program

At Randy’s, we believe in long-term relationships, not just one-time transactions. That’s why our Refresh Program is here to support you even after your warranty expires. When your transmission needs a little TLC, we’ll give it a thorough rebuild at a fraction of the cost of a new unit. It’s our way of showing our commitment to your vehicle’s performance and your satisfaction. Please remember, this program is available only to the original owner and is non-transferable. With Randy’s, you’re not just buying a transmission; you’re investing in lasting peace of mind and continued excellence on the road.

Years of Experience, Proven Results

At Randy’s, we’ve dedicated years of research, development, and testing to perfecting our transmissions. Our Stage 1 Allison 1000 isn’t just an upgrade—it’s the result of countless hours spent crafting a product that’s built to last, ensuring your Duramax runs at its best.

2005-2010 GM/ Chevy 2500 LBZ/ LMM

Allison 1000 Transmission Stage 1 500HP Max (2001-2010)

2006-2010 Chevy GMC 2500 3500 6.6L Duramax 5 Row Extruded Tube Aluminum Radiator

2001-2005 Chevy GMC 2500 3500 Duramax 5 Row Extruded Tube Aluminum Radiator