The Sonnax Performance Pack for GM 4L60-E, 4L65-E and 4L70-E transmissions is a must-have for any heavy-duty vehicle and the very best foundation for high-performance racing. All components work together to carefully tune line pressure, accumulator pressure and shift calibration. It’s the ultimate way to get an impressive transmission that responds to throttle and increased load with quick, firm shifts.

• Consistent, firmer shifts under load without sacrificing low-speed drivability or guessing on calibration
  • Faster pressure increase and higher overall pressure for greater clutch/band holding power
  • Three ultra-reliable, patented, billet pinless accumulator pistons
  • Unique 1-2 accumulator spring combination for shifts with character
  • Improved high RPM pressure
  • Third accumulator valve gets the 2-3 right the first time, every time
• Durable parts target commonly worn areas and prevent future damage to the accumulators and separator plate
• The only way to eliminate PWM function without over-pressurizing converters (optional)