Limitations of the GM 4L60E 4L65E 4L70E OE input housing are the root cause of 3-4 burn up in performance applications. The weak OE backing plate flexes during the clutch apply, allowing heat to build up unevenly within the clutch pack's limited space. Stop the flex and you stop 3-4 clutch failure.
Sonnax Smart-Tech Input Housing Kit makes room for a taller clutch pack anchored in place by a stronger backing plate, making it the only way to increase clutch capacity and protect against destructive heat. Numerous other improvements to the housing ensure maximum durability and protection against failure in higher horsepower, higher pressure applications.
Physically larger clutch pack area for increased 3-4 clutch capacity without sacrificing clutch durability. Use your choice of: Eight .067" frictions with seven .095" steels or Nine .062" frictions with eight .077" steels.
Anchored backing plate keeps clutches parallel to stop the flexing and distortion that leads to heat build up. The treated housing is significantly more resistant to fatigue failure. The steel reinforcement sleeve prevents breakage in the spline area. The custom backing plate replaces OE retaining ring to eliminate risk of blowout.
Features
PTFE Impregnated Rear Stator Support Bushing
Modified Input Housing
Input Drum Reinforcement Sleeve
Overrun Piston Inner Seal
Overrun Piston
3-4 Apply Plate
10 3-4 Clutch Return Springs
Bolt on Anchor Plate
Overrun Piston Outer Seal
15 Socket Head Cap Screws