48RE Transmission Stage 4 1,000HP+ w/ Sonnax Oversized Input Shaft

$22,878.45

48RE Transmission Stage 4 1,000HP+ w/ Sonnax Oversized Input Shaft — built and tested by Randy’s Transmissions for dependable towing and daily driving. Imported to order and backed by the team at Willys Workshop.

Imported to order — through our workshopWe bring this in from our supplier and receive it at our workshop first. From there we can build, tune or fit it for you — or ship it straight to you or your mechanic. Freight and any workshop work are quoted on enquiry.

Available to order

SKU: WEBKIT.P9 Category: Brand:
Workshop Fitment & Tuning
Built & Calibrated to Spec
Up to 24 Month Warranty

Free Shipping

Easy returns within 14 days

12 month warranty

Description

Description

Randy’s Stage 4 48RE Transmission – Unleash the Ultimate Power

For the true performance enthusiast who demands nothing less than the best, Randy’s Stage 4 48RE transmission is the pinnacle of racing and towing excellence. Rated for 1,000+ HP, this transmission is engineered to deliver unrivaled strength and performance at the track, or wherever you push your truck to the limits.

Race Ready Performance:

This Stage 4 48RE is packed with race-ready features, including our 35 Spline Triple Disc Converter, available in two stall options: Stock (Tow/Daily 1800-2000 RPM) and High (Street/Track 2400-2600 RPM). Whether you’re going full throttle on the drag strip or testing your power on the dyno, this converter ensures your truck responds with the power and precision you demand.

Transmission Specs:

  • Randy’s 35 Spline Triple Disc Converter: Available in two stalls—Stock (Tow/Daily 1800-2000 RPM) or High (Street/Track 2400-2600 RPM)—you choose the lockup based on your driving habits.
  • Alto G3 Clutches and Steels: Exclusive to Randy’s, these clutches and steels provide superior holding power and durability, designed for the toughest applications.
  • Alto G3 Power-Packed Overdrive with Custom Pressure Plate: Enhanced for high-torque conditions, ensuring smooth and efficient shifts.
  • TCS Billet Direct Drum Strengthened to handle higher torque and horsepower, improving overall performance.
  • TCS Super Servo, Billet Band Strut, Billet Wedge: Provides unmatched precision and durability for smooth, reliable shifting under pressure.
  • Billet Accumulator: Built to withstand high-pressure environments, extending the transmission’s lifespan.
  • Billet 4.2 Lever: Ensures optimal performance and durability.
  • Sonnax Billet Input Shaft (Oversized): Designed to handle extreme power output, reducing the risk of breaking.
  • Ridged 2nd Gear Band: Improves durability and shifting performance under heavy load.
  • Heavy Duty Direct Drum Piston: Built to handle higher pressures and provide consistent performance under stress.
  • Borg Warner Governor Pressure Solenoid: Ensures precise pressure control for optimized shifting and reliability.
  • High Pressure Transducer: Monitors and regulates pressure levels, ensuring smooth and efficient operation.
  • Heavy Duty Cast Aluminum Deep Pan: Offers increased fluid capacity and cooling for improved transmission life.
  • Maraging Intermediate Shaft: High-strength shaft designed for extreme conditions.
  • Big Daddy Output Shaft: Built to handle massive amounts of torque and horsepower.
  • Custom High Pressure Valve Body: Engineered to deliver high pressure for improved performance and clutch application in demanding situations.
  • PTFE Coated Thrust Washers: Provides reduced friction and wear for longer-lasting performance.
  • Optional Add-On: Upgrade to a full manual valve body for $399, which includes a billet reverse servo, giving you complete control over shifting and lockup.

Proven Power:

This is the exact transmission build that powers our legendary 2006 Ram 3500 “Red Delicious,” which put down an astonishing 3,180 HP on June 1, 2024.

It’s the same transmission backing Shawn Baca’s “Master Shredder,” propelling it to an 8.8 second ¼ mile run at 157 mph during the Ultimate Callout Challenge (UCC). These are the same internals that helped the Industrial Injection drag truck, weighing 5,445 pounds on leaf springs, shatter records with an 8.07 second ¼ mile at 180 mph during the UCC.

Featuring Alto G3 Clutches & Steels 

The Alto G3 line has a long-standing reputation for its strength and reliability in transmission builds. Developed to withstand extreme demands, G3 frictions have become the gold standard for builders who demand durability and consistent performance.

Recognizing the need for a tough, long-lasting transmission solution, we teamed up with Alto to bring a full clutch and steel lineup specifically designed for the 47RE & 48RE. Built with the same trusted G3 technology, this lineup offers unmatched resilience, ensuring your transmission can handle anything you throw at it—whether it’s the heavy demands of towing or the rigors of track racing.

This collaboration between Randy’s and Alto guarantees that your 48RE gets the best in performance, tested and proven under real-world conditions.

Backed by Real-World Testing and Proven Expertise

Since 2008, we have mastered the 48RE transmission. Through years of hands-on experience, we’ve fine-tuned our builds to deliver unmatched durability and performance. When it comes to the 48RE, nobody else comes close.

Our very own Red Delicious (2006 Cummins Dually) started with stock power, but out of a desire to find and eliminate every weak point, we steadily increased its power. Each stage of development allowed us to identify and address vulnerabilities, resulting in a transmission built to withstand anything you can throw at it. Our real-world testing ensures that every transmission we produce is battle-tested and ready for the road or track

Why Choose Randy’s Stage 4 48RE?

Performance perfected. That’s what you get with Randy’s Stage 4 48RE transmission. We’ve invested years of trial and error, pushing our builds to the absolute limit, to bring you the strongest, most reliable 48RE transmission available. This isn’t just a transmission; it’s the culmination of our dedication to providing Cummins owners with the ultimate power and performance.

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.

1-Year / 12,000-Mile Warranty

Randy’s Transmissions is committed to excellence and reliability. That’s why we offer a 1-year, 12,000-mile warranty on our products. This warranty ensures that you can drive with confidence, knowing that if any issues arise within the coverage period, our team is ready to support you. Our warranty is a testament to the high standards of quality and durability that define our transmissions, giving you peace of mind and a reliable partner on the road.

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.

Imported to Order — Through Our Workshop

  • Brought in from our supplier and received at our Sunshine Coast workshop first.
  • From there we can build, tune or fit it for you, or ship it on to you or your mechanic.
  • Freight and any workshop work are quoted on enquiry — international freight, customs and delivery vary by item and destination.
  • Typical lead time is confirmed at the time of order.

Get a freight + build quote: call (07) 5619 7869 or email sales@willysworkshop.com.au.

Randy's Transmissions — Limited Warranty

Randy's Transmissions warrants all reman transmissions, torque converters and serviced components per the published Randy's Limited Warranty:

  • 12 months / unlimited km on reman transmissions (street use)
  • Lifetime on Randy's hard parts (gears, shafts) where stated
  • Claims processed via Randy's Warranty Claims & Support form
  • Original proof of purchase required
  • Competition / off-road use excluded unless specifically stated

Fitment by Willys Workshop can be arranged in-house at our Oxley or Warana locations — workshop fitment receipts count toward warranty claim documentation.

Read the full Randy's Transmissions warranty terms →


Warranty claims are coordinated through Willys Workshop. Email sales@willysworkshop.com.au or call Warana (07) 5619 7869 / Oxley (07) 3377 3421 with your order number and a description of the issue.

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Send your rego or VIN and our Australian-based team will manually confirm fitment before you buy.
Prefer to text your rego/VIN? 0485 885 957