68RFE Category 4 Transmission - 950HP - 2007.5-2024

6.7L Cummins Ram 2500 / 3500  |  950+ HP Application Class

At 950+ horsepower, 68RFE durability depends on much more than a stronger clutch pack. High Cummins torque challenges the flexplate, input shaft, clutch hubs, one-way elements, apply pistons and hydraulic circuits as a connected system. The SunCoast Category 4 pairs our M3GA (MEGA) V2 billet drum with expanded-capacity overdrive and underdrive clutches, a one-piece billet flexplate, billet input hardware and carefully calibrated hydraulics. Every major upgrade is designed to support the next, delivering serious torque capacity with controlled, repeatable shifts.

FEATURES & BENEFITS  |  INCLUDED IN THE CAT 4 BUILD
-  SunCoast M3GA / MEGA V2 billet drum    
-  Expanded-capacity overdrive clutch pack
-  Expanded-capacity underdrive clutches    
-  SunCoast one-piece billet flexplate
-  SunCoast billet 68RFE input shaft    
-  Billet input clutch hub
-  Billet HD overdrive clutch hub    
-  SunCoast billet 2C apply piston
-  Upgraded 2C clutch set    
-  Pro-Loc Ducenti valve body
-  Heavy-duty low/reverse sprag    
-  SunCoast 4C snap-ring retainer
-  68-BTW billet 4C thrust washer    
-  Zero-Cavitation Filter Kit
-  Machined deep Mag-Hytec pan    
-  New OEM Mopar solenoid pack
-  New UD & OD molded piston set    
-  New 68RFE thrust washer kit
-  New 68RFE thrust bearing kit    
-  Complete gasket and sealing kit
-  New 68RFE spin-on filter    
-  New pan / bottom-feed filter
 
SUNCOAST M3GA / MEGA V2 BILLET DRUM  |  EXPANDED OD & UD CAPACITY
The overdrive clutches are among the 68RFE's most heavily stressed components when engine torque and clutch energy rise. SunCoast's M3GA V2 billet drum replaces the original arrangement with a more rigid housing and increased overdrive friction capacity. Its revised hydraulic geometry provides 24% greater clamping force than the factory drum, helping the clutch pack apply decisively instead of slipping and generating destructive heat.

The V2 incorporates a larger-diameter outer lip-seal surface, an inner quad-ring seal designed to retain compression at elevated RPM, and thicker drum walls to reduce apply-plate movement. The revised design also eliminates centrifugal apply springs. We pair that overdrive architecture with expanded-capacity underdrive clutches, increasing the friction interfaces available to manage torque in both circuits. The result is a stronger, more stable clutch system rather than a single isolated drum upgrade.

SUNCOAST ONE-PIECE BILLET FLEXPLATE  |  STRENGTH AT THE ENGINE INTERFACE
The flexplate is the first mechanical link between the engine and transmission. At this output, crankshaft torsional pulses and converter loading repeatedly work that interface. SunCoast's one-piece billet flexplate replaces a multi-piece-style load path with a rigid, continuous design, helping resist flexing, fatigue and distortion while maintaining consistent mounting geometry. That additional structural margin is particularly important when a high-torque Cummins is launched, loaded or subjected to abrupt torque changes.

SUNCOAST BILLET INPUT SHAFT  |  BILLET INPUT & OVERDRIVE HUBS
Category 4 does not leave the hard-part torque path to factory components. A SunCoast billet 68RFE input shaft carries the engine's torque into the transmission, while billet input and heavy-duty overdrive clutch hubs reinforce two highly loaded spline interfaces. Together with the one-piece flexplate, these parts address torsional stress, repeated torque reversals and hard-part fatigue that can become limiting factors long before a premium clutch pack reaches its full potential.

SUNCOAST BILLET 2C PISTON  |  EVEN APPLY, GREATER FRICTION CAPACITY
The factory molded 2C piston can deflect under apply pressure, loading frictions unevenly and concentrating heat in portions of the clutch pack. SunCoast's rigid billet 2C apply piston reduces that deflection and is paired with an upgraded 2C clutch set that supports an additional friction. Higher capacity matters, but even contact across the clutch faces is what helps preserve that capacity through repeated heavy-load shifts.

PRO-LOC DUCENTI VALVE BODY  |  200-PSI HYDRAULIC CONTROL
A larger clutch stack cannot hold torque without repeatable hydraulic pressure. The SunCoast Pro-Loc Ducenti valve body uses a 200-psi calibration strategy and coordinates pressure-regulator, accumulator and torque-converter-clutch circuits. Upgrades include an updated pump half, TCC limit and switch valves, five billet three-ring accumulator pistons, a billet valve-body plate, heavy-duty accumulator plate and calibrated regulator springs. The goal is consistent apply timing and controlled pressure delivery, not simply a harsh shift.

UPGRADED SPRAG, 4C RETAINER & BILLET THRUST WASHER
SunCoast's heavy-duty low/reverse sprag strengthens the one-way torque-reaction path against sudden load changes. A reinforced 4C snap-ring retainer addresses another vulnerable factory retention point, while the SunCoast 68-BTW billet 4C reaction ring gear thrust washer replaces the failure-prone OE plastic washer. These supporting components help control axial loading and retention, protecting the rotating assembly from damage that a clutch-capacity upgrade alone cannot prevent.

ZERO-CAVITATION FILTRATION  |  DEEP MAG-HYTEC PAN
The original 68RFE pan-filter and relief/check-valve design can compromise pump inlet supply when its plastic components fail. SunCoast's Zero-Cavitation Filter Kit uses a bottom-feed Torqueflite-style pickup arrangement to help maintain oil delivery and reduce the risk of pump cavitation. It is matched to a specially machined deep Mag-Hytec pan with additional fluid reserve and thermal mass. More stable fluid supply supports consistent hydraulic application; added capacity helps moderate temperature swings, but does not replace a properly functioning cooler.

NEW SOLENOIDS, PISTONS, SEALS, FILTERS & THRUST COMPONENTS
Every Cat 4 also receives the foundational upgrades found throughout the SunCoast 68RFE program: a new OEM Mopar solenoid pack, renewed underdrive and overdrive molded pistons, an upgraded 2C clutch assembly, new thrust washers and thrust bearings, a complete gasket and sealing kit, and fresh spin-on and pan-filter service components. These parts restore hydraulic sealing, mechanical support and filtration around the premium billet hardware. High horsepower is only reliable when the less-visible service components are renewed as carefully as the major assemblies.

THE CATEGORY 4 DIFFERENCE  |  PURPOSE-BUILT FOR 950+ HP
Category 4 pairs the M3GA V2 drum and expanded clutch capacity with a one-piece billet flexplate, billet input shaft and hubs, billet 2C piston and Pro-Loc Ducenti hydraulics. Reinforced 4C retention, a heavy-duty sprag, Zero-Cavitation filtration and a deep pan complete a transmission engineered for 950+ HP while preserving controlled street drivability.

SUNCOAST CAT 4  |  EVERY LINK IN THE TORQUE PATH MATTERS