Line Pressure Booster Kit

The Sonnax Line Pressure Booster Kit is engineered to enhance the performance and durability of 4L80-E and 4L85-E transmissions. This kit includes a precision-machined valve, a sleeve, a stronger pressure regulator spring (approximately 10% stronger than OE), and two O-rings. This system aims to deliver shorter, crisper shifts and increased torque capacity without introducing low-speed harshness. It also improves the holding capacity of the transmission's bands and clutches, contributing to increased overall durability. A key benefit is the controlled pressure increase, which avoids overloading the transmission pump at idle while providing optimal pressure when needed most. The Sonnax Line Pressure Booster Kit is designed as a simple, affordable drop-in solution. No special tools or reaming are required for installation, making it a convenient upgrade for transmission rebuilds or performance enhancements. The kit offers the advantages of increased line pressure with a modest increase at the low end and a high-end pressure that meets or exceeds other aftermarket spring options.