Smart-Tech® Input Housing Kit with Heavy Duty Input Shaft Part No. 77733-10KB Fits '85-later 298mm units with 30-spline input shaft. For '82-84 298mm units with 27-spline input shaft, converter and stator shaft will need to be updated to '85-later design. OE Part No. 17803689, 08663580 Limitations of the GM 4L60 series OE input housing are the root cause of 3-4 burnup in performance applications. The weak OE backing plate flexes during 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. The unique Sonnax Smart-Tech housing design 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. This kit comes with Alto's Top of the line High Performance G3 3-4 Powerpack clutches specifically designed for Sonnax Smart-Tech drum. Smart-Tech input housing kit with heavy duty input shaft 77733-10K fits 298mm torque converter units. The high-strength shaft features many unique refinements available only from Sonnax, including a unique design that protects against failure from stress cracks. Both the housing and shaft also are available separately. 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 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 Treated housing is significantly more resistant to fatigue failure Steel reinforcement sleeve prevents breakage in the spline area Custom backing plate replaces OE retaining ring to eliminate risk of blowout Learn more about the Sonnax Smart-Tech Input Housing Note: Requires '91-later 3-4 apply ring; requires '97-later ring gear; requires '97-later stamped steel forward piston; requires '97-later dual-cage return spring. Cannot be used with aluminum forward piston or Sonnax billet forward piston 77764-01. See instructions for further detail. Contents: Smart-Tech® Input Housing with 298mm Input Shaft Assembly PTFE Impregnated Rear Stator Support Bushing Input Drum Reinforcement Sleeve installed Overrun Piston Inner Seal 3-4 Clutch Apply Plate 3-4 Clutch Return Springs (10) Bolt-on Anchor Plate Overrun Piston Outer Seal Socket Head Cap Screws (15) Overrun Piston