OE has made multiple pump design changes. Transmission will not function properly if the wrong length sleeve is installed. Verify length of OE sleeve and select Sonnax kit with equivalent sleeve length.

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

Line Pressure Booster Kit
Part No. 4L60E-LB1

Early style

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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 harshness
  • Improved band and clutch holding capacity for increased durability
  • Progressive pressure increase as driving conditions become more demanding
  • All the benefits of increased line pressure without overloading the pump at idle
  • Drop-in Zip Valve parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs

Replaces early-style boost valve with "long" 1.907" sleeve. For applications with "short" 1.810" sleeve use 4L60E-LB2. See instructions for additional application information.

  • Pressure Regulator Spring
  • O-Rings (2)
  • Large Ratio Boost Assembly

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 4L60-E, 4L65-E, 4L70-E Valve Body Layout

GM 4L60-E, 4L65-E, 4L70-E Valve Body Layout

  • 4L60-E, 4L65-E, 4L70-E Line Pressure Booster Kit 4L60E-LB1
  • 4L60-E, 4L65-E, 4L70-E Line Pressure Booster Kit 4L60E-LB1
  • 4L60-E, 4L65-E, 4L70-E Line Pressure Booster Kit 4L60E-LB1 details


Eliminate Leakage & Optimize Performance with Sonnax O-Ringed Valves
Sonnax Line Pressure Booster Kit

Sonnax Line Pressure Booster Kits

Crisp, clean shifts without harshness

Sonnax booster kit components are uniquely designed for precision pressure control. At low-end pressures, they deliver normal engagements, normal light throttle shifts and smooth coastdown shifts. When vehicles are pushed harder, components progressively increase pressure for improved clutch holding capacity and increased durability.

Learn more about Line Pressure Booster Kits