4L60E 4L65E 4L70 4L70-E SONNAX HP-4L60E-01 PERFORMANCE PACK 1994-ON. THIS KIT WILL FIT THESE AUTOMATIC TRANSMISSIONS GMC CHEVY BUICK CADILLAC PONTIAC OLDSMOBILE 4L60E 1994-ON 4L65E 2001-ON 4L70 SONNAX Part No. HP-4L60E-01 PUMP PARTS INCLUDE: Boost Valve with O-Ring, .490� Elevated Pressure Regulator Spring High RPM Pump Slide Spring 1 Spacer SERVO PARTS INCLUDE: 4th Servo Return Spring Servo Cushion Spring Servo Piston D-Ring Kit CASE PARTS INCLUDE: 3-4 Accumulator Piston Kit 3-4 Accumulator Spring Servo Release Check Valve BODY PARTS INCLUDE: Forward Accumulator Kit Accumulator Valve Shim Twist Drills ACCUMULATOR PARTS INCLUDE: 1-2 Pinless Accumulator Piston Kit 1-2 Accumulator Inner Spring 1-2 Accumulator Outer Spring 1-2 Accumulator Waved Spring Accumulator Housing Spacer Features & Benefits � Shorter shifts which get progressively firmer with load � 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 � Consistent results, no guessing on calibration � Prevents worn accumulators and separator plate � Optional TCC on-off conversion prevents excess TCC pressure Sonnax Performance Pack HP-4L60E-01 combines innovative heavy duty/performance calibration for firmer shifts under load without sacrificing low-speed drivability. The precision components in this kit upgrade the 4L60-E for maximum performance and durability by recalibrating pressures, recalibrating shift accumulation and including improved parts for areas that commonly wear. This kit is suitable for any heavy duty application and is a critical foundation for other upgrades when modifying the 4L60-E for high performance use.