Ram 68RFE Transmission Rebuilds & Performance
The 68RFE, Perfected for the Arizona Heat.
The stock 68RFE is known for its weak points: cross-leaks, valve body warping, and premature overdrive clutch failure. At Tier One Transmissions, we don't just rebuild them; we engineer the failure points out. As Phoenix’s highest-volume 68RFE builder, we offer distinct tiers designed for how you use your truck.
Don't settle for a stock replacement that will fail again. Get a Tier One built 68RFE, dyno-tested and proven on the streets of Phoenix.
The Tier One Difference: Testing & Reliability
We take pride in every built 68RFE transmission we manufacture for Ram 6.7L Cummins trucks. To ensure you get a transmission as tough as your truck, we put our components through rigorous testing before they ever leave our shop.
- Valve Body Testing: Every valve body is flat-sanded, vacuum-tested, and run through a rigorous dyno-test to ensure proper fluid flow, line pressures, and solenoid operation.
- Transmission Dyno: After final assembly, we put the transmission through a complete air-check to find potential leaks, followed by a session on our in-house transmission dyno to ensure proper operation and power-holding.
- The "Arizona Heat" Standard: We utilize deep cast aluminum pans and high-pressure valve bodies to manage heat, ensuring your truck survives heavy towing in desert conditions.
Choose Your 68RFE Build Level
1. The "Tow-All" HD 68RFE
Best For: Heavy towing, work trucks, and near-stock power applications.
The stock 68RFE handles street driving fine, but struggles the moment you tow near GVWR. The Tow-All is built from the ground up to handle heavy, consistent towing. It features heavier-duty internals than stock, a deeper transmission pan for cooling, and a high-pressure valve body to route fluid effectively.
- Torque Converter: Precision Billet Twin-Disc Low Stall.
- Key Upgrades: Switch Valve Repair Kit, Billet Accumulator Kit, Billet 4C Spring Retainer.
- Reliability: Includes TIG-welded planetary pinions and new Borg Warner frictions.
2. Stage 1 (ST1+) 68RFE
Best For: Daily driving with mild tuning (Up to 600HP).
Our most popular daily driver build. If you are running a mild tuner or pushing your towing capacity to the limit, the stock unit gets unhappy fast. The Stage 1 is designed to hold extra power without failing. It includes a Laser Separator Plate and Billet Accumulator Cover Plate to avoid codes.
- Power Rating: ~600 HP.
- Torque Converter: Precision Billet Twin-Disc.
- Key Upgrades: High-Pressure Valve Body, Upgraded OD/UD pressure plate snap ring to prevent walk-out.
3. Stage 2 (ST2) 68RFE
Best For: Aggressive tuning, larger turbos, off-road rigs, and mixed street/strip use.
The ultimate street performance transmission. Capable of handling up to 750 HP, this unit is built for trucks with upgraded turbos, injectors, and bolt-on mods. It features a full suite of billet components to resist breakage under high load.
- Torque Converter: SunCoast Cat 1 Billet Triple-Disc.
- Billet Hard Parts: Sonnax 300M Billet Input Shaft, Billet Input Clutch Drum, Billet 4C Retainer, Billet 2C Piston.
- Clutches: Increased count with 14 overdrive clutches.
4. Stage 3 (High Performance) 68RFE
Best For: Sled pulls, drag racing, and 900+ HP builds.
When you are stacking massive turbos and nitrous, you need the Stage 3. This transmission fixes critical flaws to handle extreme torque. It features a Sonnax Smart Tech Drum that is far stronger than stock to avoid flex under extreme power loads.
- Power Rating: Up to 900 HP.
- Torque Converter: SunCoast Billet Triple-Disc with Billet Stator.
- Extreme Upgrades: TCS Billet Maraging Steel Input Shaft, Billet Center Support, Billet OD Clutch Hub (One-piece).
Important Tuning & Gear Ratio Requirements
To ensure the longevity of your Tier One transmission and to maintain your warranty, the following specifications must be met:
Tuning Notes
- Line Pressure: High-pressure VB needs to be at 225psi at 25-30% throttle angle (Stock is 160psi). Reverse should reach 250psi.
- Lock Strategy: Factory lock strategy must be used to avoid damage.
- UD Pulse: 2019+ models should have UD pulse turned off (Verify on 2017-18 models).
- Relearn: Every 68RFE must have a relearn completed upon install.
Recommended Gearing
Proper gearing relieves stress on the transmission. We require the following gears for warranty coverage:
| Tire Size | Required Gear Ratio |
|---|---|
| 35" Tire | 4.10 or higher |
| 37" Tire | 4.30 or higher |
| +38" Tire | 4.56 or higher |
Where R&D Meets the Drag Strip
At Tier One Transmissions, we don't just build transmissions; we break them, improve them, and race them. Our "Test Bed" Race Truck is the fastest 68RFE in Arizona (5.795 @ 660' and .128 60').
We use our race program to push the 68RFE platform to its absolute limits—aiming for over 2000HP in our current "Round 2" build featuring a Tier One Competition All-Out Transmission. When you buy a transmission from us, you are buying technology proven on the track.
Ready to build your truck?
If you have questions or want a custom 68RFE build, contact the experts.
Call Tier One: 602-399-5484
All Tier One built transmissions are backed by a 2-Year, Unlimited Mile Warranty.
