4L60E 700R4 Smart-Tech® Input Housing Kit w/ Heavy Duty Input Shaft (298mm) Sonnax (NLA)

Product Description

Sonnax Smart-Tech input housing kit with heavy duty input shaft, part number 77733-10K, for GM 4L60 series and 700R4 transmissions with 298mm torque converters. It fits '85-later 298mm units with a 30-spline input shaft and increases 3-4 clutch capacity for higher horsepower, higher pressure applications.

Specifications

How it works

The weak OE backing plate in the GM 4L60 series input housing flexes during clutch apply, letting heat build up unevenly in the limited clutch pack space. This is the root cause of 3-4 clutch burnup in performance applications.

The Smart-Tech housing makes room for a taller 3-4 clutch pack, anchored by a stronger bolt-on backing plate that keeps the clutches parallel. The housing is treated to resist fatigue failure, a steel reinforcement sleeve prevents breakage in the spline area, and a custom backing plate replaces the OE retaining ring to eliminate the risk of blowout. The high-strength input shaft is designed to resist failure from stress cracks. The housing and shaft are also available separately.

Clutch pack choices: eight .067 in frictions with seven .095 in steels, or nine .062 in frictions with eight .077 in steels.

For '82-84 298mm units with a 27-spline input shaft, the converter and stator shaft need to be updated to the '85-later design.

What's included

• Smart-Tech input housing with 298mm input shaft assembly
• Input drum reinforcement sleeve (installed)
• PTFE impregnated rear stator support bushing
• Overrun piston
• Overrun piston inner seal
• Overrun piston outer seal
• 3-4 clutch apply plate
• 3-4 clutch return springs (10)
• Bolt-on anchor plate
• Socket head cap screws (15)