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Sonnax 77898E-3K 4L60E Transmission Boost Valve & Sleeve Kit (.490" Diameter)

by Sonnax
Original price $22.74 - Original price $22.74
Original price
$22.74 - $22.74
Current price $22.74
in stock, ready to be shipped

Delivery time

You will receive your package in 2–5 business days within the contiguous U.S.

Brand: Sonnax

Other Part Number: S74507FB

Interchange Part Number: S74507TFK

Items Included: Line Pressure Boost Valve Kit

Manufacturer Part Number: 77898E-3K

Universal Fitment: Yes

Vintage Part: No

Performance Part: Yes

4L60-E, 4L65-E Transmission

Boost Valve Kit
Part No. 77898E-3K

Early pump design, .490" dia., factory style with increased ratio

GM 4L60-E and 4L65-E transmissions frequently have poor line rise, which can result in 3-4 clutch, 2-4 band failure or poor shift quality. The duty cycle of the EPC solenoid causes the boost sleeve to wear quickly. Oil entering the torque signal orifice leaks past the boost valve and exhausts at the Reverse orifice, resulting in poor line rise. Reverse oil can exhaust both to the sump and back through the torque signal orifice. The outside diameter of the boost sleeve also allows some leakage through the pump body, which decreases pressure rise.

Sonnax boost valve kit 77898E-3K is an increased ratio assembly that will restore hydraulic integrity and prevent leakage in units with early-design pumps. See chart for usage details and other boost valve options.

  • Sleeve
  • Valve .490", No Groove

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