The Sonnax Smart-Tech input housing kit 77733-06KA addresses five weak areas of the GM 700R4, 4L60E, 4L65E, 4L70E input housing: (1) flexing/bowing of the 3-4 backing plate, (2) limited 3-4 clutch torque capacity, (3) 3-4 snap-ring blow-out, (4) input housing breakage near the input shaft spline, and (5) input housing fatigue failure.

Flexing/bowing of OE and other aftermarket backing plates is eliminated with Sonnax’s heavy duty bolt-on anchoring plate. This unique design ensures even clamping of the 3-4 clutches in higher horsepower, higher pressure applications. By eliminating the 3-4 snap ring and using a thinner yet stiffer apply plate, space is made available for additional frictions and steels. This makes it possible to simultaneously increase clutch torque capacity and eliminate the possibility of retaining ring blow-out. A steel reinforcement sleeve prevents breakage in the spline area. Housing fatigue failure resistance and housing life are significantly improved with a special treatment process that greatly reduces stress crack formation.

Demonstration showing the 4L60E 3-4 clutch pressure plate flexing with only 110 PSI apply pressure. This is a Brand New GM pressure plate with HD stamped on it (the strongest GM). The fixtures are two 10-32 nuts glued with epoxy to opposite sides of the top of the pressure plate. Eye bolts are screwed into the nuts and aluminum rods inserted into the eyebolts. This visually demonstrates the bowing/ flexing/ dishing that happens to the 3-4 clutch applies. You can only imagine the extreme flexing that takes place on a quick apply at a 190 PSI. This is exactly why this clutch pack has such a terrible reputation.Features and Benefits

Zero-Flex, bolt-on 3-4 clutch backing plate eliminates uneven clamping pressure, resulting in increased clutch durability Increased 3-4 clutch torque capacity will accept either: Eight .067″ frictions with seven .095″ steels Nine .062″ frictions with eight .077″ steels Eliminates snap ring blow out Special Treated housing is significantly more resistant to fatigue failure Includes steel reinforcement sleeve and overrun piston.

• Zero-flex, bolt-on bolt-on anchor plate eliminates uneven clamping pressure, resulting in increased clutch durability
• Increased 3-4 clutch torque capacity will accept either:
  • Eight .067″ frictions with seven .095″ steels
  • Nine .062″ frictions with eight .077″ steels
• Eliminates snap-ring blow-out
• Treated housing is significantly more resistant to fatigue failure
• Includes steel reinforcement sleeve and overrun piston
  

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