Symptoms:

  • Reduced 3-4 clutch life
  • 2-3 Shift feel poor
  • 3-2 Bind-up

Cause:

Inadequate metering of the 2nd band servo release oil.

Correction:

Sonnax drop-in servo release check valve kit combines an orifice with a ball check valve to meter servo release oil.

Warning:

Must be used with properly functioning OE capsule.

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

Servo Release Check Valve Kit
Part No. 77701-076

2nd Gear Servo Release

View Instructions Find a Distributor

Technicians would like to find a way to successfully extend the life of 3-4 clutches, and improve the 2-3 shift feel. They have been trying, with limited success, since the GM 4L60 (700-R4) and 4L60-E series transmissions were introduced. Inadequate metering of 2nd gear band servo release oil causes 3-4 clutch failure. The 3-4 clutch and 2nd gear band are not properly synchronized. Sonnax servo release check valve kit 77701-076 is a unique solution that combines an orifice with a ball check valve to resolve these problems.

  • Improved design meters servo release oil, reducing 3-4 clutch failure
  • Provides sufficient exhaust so that 3-2 downshifts are smooth
  • Calibrates 3-4 clutch feed orifice without creating shift concerns
  • Drop-in Zip Valve™ parts install quickly and easily

  • 4L60, 4L60-E, 4L65-E, 4L70-E Servo Release Check Valve Kit 77701-076
  • 4L60, 4L60-E, 4L65-E, 4L70-E Servo Release Check Valve Kit 77701-076
  • 4L60, 4L60-E, 4L65-E, 4L70-E Servo Release Check Valve Kit 77701-076
  • 4L60, 4L60-E, 4L65-E, 4L70-E Servo Release Check Valve Kit 77701-076 details

I use Sonnax products in almost all transmissions I build. The servo release check valve 77701-076 is probably the most used Sonnax product I have in my shop. 

B. Cumbie
5C Transmission Service & More
Jacksonville, TX