Line Pressure Booster Kit4L60-E, 4L65-E, 4L70-EFits Early-Style Pump Early-style pumpValveSleevePressure Regulator SpringO-Rings (2)Line pressure booster kit 4L60E-LB1 fits early-style GM 4L60-E, 4L65-E and 4L70-E pumps. Sonnax hydraulic line pressure booster kits contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases as driving conditions become more demanding.Our pressure regulator springs are approximately 10 stronger than OE and more conservative in impact than other aftermarket kit springs. Large ratio boost valves provide higher pressure incrementally and when it is needed the most. The combination of these springs and valves in a Sonnax kit gives you the best of both worlds: a modest pressure increase at the low end, with a high-end pressure that is equal to or greater than that of other aftermarket kit springs.Achieve shorter shifts and increased torque capacity without creating low-speed harshnessImproved band and clutch holding capacity for increased durabilityProgressive pressure increase as driving conditions become more demandingAll the benefits of increased line pressure without overloading the pump at idleSimple and affordable drop-in solution with no special tools or reaming requiredNOTE: Fits early-style pump with long 1.907" sleeve only. Use 4L60E-LB2 for later pumps with short, 1.810" sleeve