4L60-E, 4L65-E, 4L70-E

Heavy Duty Input Shaft
Part No. 77733-12SB

For units with 300mm converter, reluctor-style shaft.

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Input shaft failure is a common problem in GM 4L60-E, 4L65-E, 4L70-E units as power levels are increased. Sonnax heavy duty input shaft 77733-12SB for 300mm torque converter, reluctor-style units is ideal for any high-horsepower street or strip application. The shaft is manufactured from 300M ultra high-strength steel for exceptional toughness and resistance to fracture. It features a revised turbine end spline without an undercut where OE shafts commonly break.

  • High-strength 300M steel shaft is more than 2X stronger than OE
  • Shot peened for extreme durability
  • Unique design protects against failure from stress cracks
  • 4L60-E, 4L65-E, 4L70-E Heavy Duty Input Shaft 77733-12SB


Harness that Horsepower! Your Guide to a Sonnax 4L60/E Level 3 Performance Build