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Sonnax 77898E-16K Boost Valve Kit 4L60E 4L65E 4L70E Late pump design, .472" dia

Sonnax 77898E-16K Boost Valve Kit 4L60E 4L65E 4L70E Late pump design, .472" dia

by Sonnax
SKU S74507THK
$34.70 - $34.70
$34.70
$34.70 - $34.70
$34.70
Availability:
in stock, ready to be shipped

Delivery time

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

OE Spec or Performance/Custom: Performance/Custom

Brand: Sonnax

Interchange Part Number: S74507THK

Manufacturer Warranty: No Warranty

Items Included: Line Pressure Boost Valve Kit

Manufacturer Part Number: 77898E-16K

Country/Region of Manufacture: United States

Universal Fitment: Yes

Vintage Part: No

Performance Part: Yes

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

Boost Valve Kit
Part No. 77898E-16K

Late pump design, .472" dia., O-ring style with OE ratio

GM 4L60-E, 4L65-E and 4L70-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-16K is a large OE ratio assembly that will restore hydraulic integrity and prevent leakage in units with late-design pumps. Drop-in Zip Valve™ parts install quickly and easily. See chart below for usage details and other boost valve options.

  • Valve 4 Grooves, .472" dia.
  • Sleeve
  • O-Rings (3) 1 Extra

Symptoms:

  • 3-4 Clutch failure
  • 2-4 Band failure
  • Low line rise
  • Poor shift quality

Cause:

A worn boost sleeve can allow torque signal and Reverse oil cross-leakage or leakage to sump.

Correction:

Sonnax drop-in boost valve kit restores hydraulic integrity and prevents leakage.

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