Sonnax Servo Release Check Valve Kits

Sonnax servo release check valve kits are unique solutions. Since the GM 4L60 (700-R4) and 4L60-E Series transmissions were introduced, they have had inadequate metering of 2nd gear band servo release oil resulting in 3-4 clutch pack failure. The 3-4 clutch pack and 2nd gear band are just not properly synchronized. Sonnax servo release check valve kits combine an orifice with a ball check valve to resolve these issues and successfully extend the life of 3-4 clutches, and improve the 2-3 shift feel. Other benefits: * Provides sufficient exhaust so that 3-2 downshifts are smooth * Calibrates 3-4 clutch feed orifice without creating shift concerns Show Less