4L80-E, 4L85-E

Performance Pack
Part No. HP-4L80E-01

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Sonnax Performance Pack HP-4L80E-01 upgrades GM 4L80-E and 4L85-E transmissions for maximum performance and durability in work/sport vehicles. Innovative components work together to precisely recalibrate pressures and shift accumulation, delivering firmer shifts under load without sacrificing low-speed drivability. To target common wear areas in the transmission, the kit includes many improved parts to repair damage, prevent future wear and improve reliability.

  • Recalibrated shift accumulation, with tunability for great, heavy-duty shifts
  • Improved pump components minimize leaks, plus maintain pressure and lube under demanding use
  • The only way to eliminate TCC PWM function without over-pressurizing the converter
  • Includes internal parts for setup and to prevent common failures
  • Line Pressure Booster Kit
  • Lube Regulated Pressure Regulator Valve
  • TCC Pressure Limiter Valve, Spring & Plug
  • AFL Filter End Plug & O-Ring Kit
  • Direct Clutch Dual Feed Plug
  • Direct Clutch Dual Feed Aluminum Plugs (3) 2 Extra
  • 1-2, 2-3 & 3-4 Accumulator Piston Springs (3)
  • Checkballs (8)
  • Twist Drill .062"
  • Twist Drill .086"
  • Heavy Duty Case Bushing & Bearing Kit
  • Direct Housing Support Ring & Seal
  • Heavy Duty Intermediate Piston Spring Retainer Plate
  • Case Saver Retainer
  • Heavy Duty Clutch Retaining Ring Intermediate Clutch
  • Accumulator Valve Springs & Adjustable End Plug 2 Springs
  • Heavy Duty Direct Piston Return Springs (8)
  • Forward Clutch Hub Front Washer .078"
  • Reverse Servo Spacer Kit

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

GM 4L80-E, 4L85-E, TH400 Valve Body Layout

GM 4L80-E, 4L85-E, TH400 Valve Body Layout
  • 4L80-E, 4L85-E Performance Pack HP-4L80E-01


See What's Inside the Sonnax 4L80-E Performance Pack
Sonnax Performance Pack

Sonnax Performance Packs

The Best Parts for Performance & Heavy Duty Recalibration

Performance enthusiasts look to Sonnax when building stronger, faster, more reliable transmissions. Performance Packs combine key Sonnax performance and heavy duty parts into powerhouse kits which take transmissions to the next level.

Learn More about Sonnax Performance Packs